diff --git a/BuildController.gd b/BuildController.gd
index 6a45e1e..c9bc7d0 100644
--- a/BuildController.gd
+++ b/BuildController.gd
@@ -195,7 +195,56 @@ var pending_time: float = 0.0
 var context_actions_expanded: bool = false
 
 
+# Gap between the last resource row and the first row of HUD buttons.
+const HUD_COLUMN_MARGIN: float = 18.0
+
+
+# Seats the top-anchored HUD button columns below the resource readout instead
+# of at the fixed y the scene authored.
+#
+# ResourceReadout builds one row per resource type AT RUNTIME, so how far down
+# it reaches is not knowable when the scene is laid out - the scene's guess
+# was 154, and four resources actually reach 270, straight over the build
+# button sitting at a hardcoded 160. Every resource type added since made it
+# worse. Deriving the column top from the readout's real bottom makes the
+# overlap impossible rather than merely fixed for today's resource count.
+#
+# This TRANSLATES the block rather than re-flowing it, so the rows keep their
+# spacing relative to one another - BuildingActionButton and HangarButton
+# deliberately share a row, being mutually exclusive, and a flow layout would
+# pull them apart.
+func _seat_hud_columns() -> void:
+	var readout: ResourceReadout = get_node_or_null("../UI/ResourceReadout")
+	if readout == null:
+		return
+	# Both columns, not just the left one: the readout spans the full width
+	# (the fleet hold column sits at x 356), so the second column of buttons
+	# collides with it exactly as the first does.
+	var buttons: Array = [
+		build_button, transfer_button,
+		action_button, landing_button,
+		building_action_button, hangar_button,
+	]
+	var highest: float = INF
+	for button in buttons:
+		if button != null:
+			highest = minf(highest, button.position.y)
+	if is_inf(highest):
+		return
+
+	var shift: float = readout.content_bottom() + HUD_COLUMN_MARGIN - highest
+	# Only ever pushed down, never pulled up: with few enough resources the
+	# authored layout already clears the readout, and there is no reason to
+	# drag the HUD away from where the scene deliberately put it.
+	if shift <= 0.0:
+		return
+	for button in buttons:
+		if button != null:
+			button.position.y += shift
+
+
 func _ready() -> void:
+	_seat_hud_columns()
 	build_button.pressed.connect(_on_build_pressed)
 	build_close_button.pressed.connect(_close_build_menu)
 	_configure_build_menu_entries()
diff --git a/Fleet.gd b/Fleet.gd
index ef17702..dae7f48 100644
--- a/Fleet.gd
+++ b/Fleet.gd
@@ -238,33 +238,25 @@ func stop() -> void:
 	# since that lands inside arrive_radius immediately).
 	fleet_target = get_formation_origin()
 	for ship in ships:
-		# A ship's own `velocity` is NOT how fast it is really travelling
-		# while the fleet cruises. Ship snaps to its slot and reports zero
-		# the moment it is within arrive_radius of it, even though the
-		# anchor is dragging that slot forward at cruise_speed underneath
-		# it. Its true motion is its catch-up velocity PLUS the fleet's,
-		# which it already carries as `fleet_velocity` (zero for a
-		# point-to-point move_to, where `velocity` alone is the whole
-		# story).
+		# A ship's `velocity` is already its true motion, including the
+		# fleet's travel, because Ship feeds the slot velocity forward into
+		# its own steering rather than carrying it in a separate field. So
+		# stopping is only a matter of telling it the slot has halted and
+		# aiming it at the point its own braking curve reaches.
 		#
-		# Braking from `velocity` alone therefore stopped the fleet dead
-		# on any frame where the ships happened to be seated - and how
-		# often that happens depends on the frame rate, because the anchor
-		# advances cruise_speed * delta per frame. At ~25fps it steps far
-		# enough that ships always lag and always report motion, which is
-		# the only reason releasing the stick looked right.
-		var motion: Vector2 = ship.velocity + ship.fleet_velocity
-		# HAND THE FLEET'S MOTION TO THE SHIP. Until now the anchor was
-		# carrying it along and its own `velocity` was ~0, so aiming it at a
-		# braking point ahead made it start from REST: the fleet stopped
-		# dead, then accelerated into its own stopping distance and halted a
-		# second time. That is the "pause, then it moves again" stutter.
-		# Giving it the velocity it was actually travelling at makes the
-		# stop one continuous decelerating coast.
-		ship.velocity = motion
-		# Context that is no longer true: the fleet is not cruising any
-		# more, so leaving it set would have Ship face a heading it is not
-		# travelling on.
+		# This used to do `ship.velocity += ship.fleet_velocity` here, to
+		# compensate for `velocity` reading zero while the ship was in fact
+		# cruising (Ship snapped to its slot every tick and zeroed it). That
+		# compensation was an unbounded ACCUMULATOR: every release added a
+		# whole cruise velocity, the next steer refilled fleet_velocity, and
+		# tapping a direction repeatedly stacked them up faster than
+		# `acceleration` could bleed them off - so a vessel could be flung
+		# along at many times its own top speed, and ships fell out of sync
+		# because each bled off at a rate set by its own distance to its
+		# slot. Ship now bounds its total speed every tick as well, so
+		# neither half of that can come back.
+		var motion: Vector2 = ship.velocity
+		# The fleet is not cruising any more, so the slot is standing still.
 		ship.fleet_velocity = Vector2.ZERO
 		var speed: float = motion.length()
 		if speed <= 0.001:
diff --git a/LunarBackground.gd b/LunarBackground.gd
index af4f9d8..8b85533 100644
--- a/LunarBackground.gd
+++ b/LunarBackground.gd
@@ -3,17 +3,142 @@ extends ColorRect
 # Feeds the lunar shader the camera's position split into a CELL INDEX plus
 # a fraction within that cell, rather than a raw world position. See the
 # long note in Starfield.gd for why - identical reasoning, identical split.
+#
+# Forgejo #68: also bakes the crater field once, at load, instead of letting
+# it be re-derived per pixel per frame. The field is a fixed function of
+# world position, so every frame was recomputing an identical answer. It is
+# rendered once into a square texture covering one period of the field (the
+# field is periodic - see the cell wrap in lunar_surface.gdshader) and
+# lunar_tiled.gdshader then scrolls that texture with repeat wrapping, which
+# keeps the canvas infinite while the per-frame cost drops to one fetch.
+
+# Single source of truth for the tile period, shared with BOTH shaders. The
+# field repeats every TILE_CELLS * cell_size world units - at 32 cells of
+# 220 that is 7040 units, several screens wide at default zoom.
+const TILE_CELLS: float = 32.0
+# Texture resolution for the bake, in pixels per cell. One cell is cell_size
+# (220) world units, so this is a ~3.4x magnification at default zoom. That
+# is affordable because the field is smooth by construction: the sharpest
+# feature is the rim band, roughly 0.12 cells wide, which still lands across
+# ~8 texels here and so survives bilinear magnification as a gradient rather
+# than as steps.
+const BAKE_PIXELS_PER_CELL: int = 64
+
+# The palette, sampled from a NASA Artemis lunar photograph. These live on
+# the node rather than as parameters of the drawing material because the
+# shader that actually consumes them is the BAKE shader, which the scene
+# never references directly - leaving them as orphan parameters on the tiled
+# material would make them look live when they are only read once at load.
+@export var base_color: Color = Color(0.75, 0.75, 0.76)
+@export var crater_color: Color = Color(0.44, 0.44, 0.45)
+@export var highlight_color: Color = Color(0.89, 0.89, 0.90)
 
 @onready var camera: Camera2D = get_node("../../Camera2D")
 
 
+func _ready() -> void:
+	_bake_field()
+
+
+# Asked of the shader itself rather than by comparing against a known path,
+# so this keeps working whichever shader a surface profile swaps in: the
+# question is only ever "does what is drawing this background actually
+# sample a baked field".
+func _material_wants_baked_field() -> bool:
+	if material == null or material.shader == null:
+		return false
+	for uniform in material.shader.get_shader_uniform_list():
+		if String(uniform.get("name", "")) == "field_texture":
+			return true
+	return false
+
+
 func _process(_delta: float) -> void:
 	var viewport_size: Vector2 = get_viewport_rect().size
 	var cell_size: float = material.get_shader_parameter("cell_size")
 	var p: Vector2 = camera.global_position / cell_size
 	var cell: Vector2 = Vector2(floor(p.x), floor(p.y))
 
-	material.set_shader_parameter("camera_cell", cell)
+	# The tiled shader samples a repeating texture, so only the camera's
+	# position WITHIN the tile matters. Wrapping here rather than in the
+	# shader keeps the raw cell index - which reaches the thousands after a
+	# while - out of a mobile float entirely: GDScript does this in double
+	# precision. fposmod, not fmod, so flying into negative coordinates
+	# wraps to the far side of the tile instead of mirroring.
+	material.set_shader_parameter("camera_cell", Vector2(
+		fposmod(cell.x, TILE_CELLS), fposmod(cell.y, TILE_CELLS)))
 	material.set_shader_parameter("camera_frac", p - cell)
 	material.set_shader_parameter("camera_zoom", 1.0 / camera.zoom.x)
 	material.set_shader_parameter("viewport_size", viewport_size)
+	material.set_shader_parameter("tile_cells", TILE_CELLS)
+
+
+# Renders exactly one period of the procedural field into a texture and hands
+# it to the tiled shader. Runs once, during the planet-arrival fade, where a
+# single expensive frame is invisible.
+func _bake_field() -> void:
+	# Headless runs - every scene-based test - rasterize nothing, so a bake
+	# would allocate a render target, await a draw that never produces
+	# anything readable, and leave this coroutine suspended forever holding
+	# the SubViewport alive. Nothing is lost by skipping: there is no display
+	# for the background to appear on.
+	if DisplayServer.get_name() == "headless":
+		return
+
+	# One frame of grace before committing to the bake. A surface profile can
+	# replace this material's shader outright - a gas giant brings its own
+	# background (#51) - and PlanetSurfaceController does that in _ready(),
+	# alongside this one, with no ordering guarantee between them. Rendering
+	# a 2048-square lunar tile for a shader that will never sample it would
+	# waste exactly the frame the player is already waiting on to land.
+	await get_tree().process_frame
+	if not _material_wants_baked_field():
+		return
+
+	var procedural: Shader = load("res://lunar_surface.gdshader")
+	if procedural == null:
+		push_warning("lunar background: could not load the field shader to bake")
+		return
+
+	var side: int = int(TILE_CELLS) * BAKE_PIXELS_PER_CELL
+	var bake_material := ShaderMaterial.new()
+	bake_material.shader = procedural
+	# Carry the look across from whatever the scene configured, so the tile
+	# is baked with the colours actually set on this node rather than the
+	# shader's own defaults.
+	bake_material.set_shader_parameter("base_color", base_color)
+	bake_material.set_shader_parameter("crater_color", crater_color)
+	bake_material.set_shader_parameter("highlight_color", highlight_color)
+	bake_material.set_shader_parameter("cell_size", material.get_shader_parameter("cell_size"))
+	bake_material.set_shader_parameter("tile_cells", TILE_CELLS)
+	# Non-zero switches the field shader into bake mode: UV maps straight
+	# onto one tile and the per-screen-pixel dither is left out.
+	bake_material.set_shader_parameter("bake_cells", TILE_CELLS)
+
+	var sub_viewport := SubViewport.new()
+	sub_viewport.size = Vector2i(side, side)
+	sub_viewport.disable_3d = true
+	sub_viewport.transparent_bg = false
+	sub_viewport.render_target_update_mode = SubViewport.UPDATE_ONCE
+	var bake_rect := ColorRect.new()
+	bake_rect.material = bake_material
+	bake_rect.size = Vector2(side, side)
+	sub_viewport.add_child(bake_rect)
+	add_child(sub_viewport)
+
+	# One frame for the SubViewport to actually draw, then read it back.
+	await RenderingServer.frame_post_draw
+	var image: Image = sub_viewport.get_texture().get_image()
+	sub_viewport.queue_free()
+
+	# Headless runs (every scene-based test) render nothing at all, so there
+	# is no image to read back. That is not a failure: the background simply
+	# has nothing to show, and the rest of the scene is unaffected.
+	if image == null or image.is_empty():
+		return
+
+	# Mipmaps are what keep a crater field from shimmering when the camera
+	# zooms out and each screen pixel starts covering many texels.
+	image.generate_mipmaps()
+	var texture := ImageTexture.create_from_image(image)
+	material.set_shader_parameter("field_texture", texture)
diff --git a/PlanetSurface.tscn b/PlanetSurface.tscn
index 56e8577..199cdf8 100644
--- a/PlanetSurface.tscn
+++ b/PlanetSurface.tscn
@@ -2,7 +2,7 @@
 
 [ext_resource type="Script" path="res://GameController.gd" id="1"]
 [ext_resource type="Script" path="res://LunarBackground.gd" id="2"]
-[ext_resource type="Shader" path="res://lunar_surface.gdshader" id="3"]
+[ext_resource type="Shader" path="res://lunar_tiled.gdshader" id="3"]
 [ext_resource type="Script" path="res://Fleet.gd" id="4"]
 [ext_resource type="Script" path="res://PlanetSurfaceController.gd" id="5"]
 [ext_resource type="Script" path="res://IconButton.gd" id="6"]
@@ -15,13 +15,12 @@
 
 [sub_resource type="ShaderMaterial" id="1"]
 shader = ExtResource("3")
-shader_parameter/camera_pos = Vector2(0, 0)
+shader_parameter/camera_cell = Vector2(0, 0)
+shader_parameter/camera_frac = Vector2(0, 0)
 shader_parameter/camera_zoom = 1.0
 shader_parameter/viewport_size = Vector2(720, 1280)
 shader_parameter/cell_size = 220.0
-shader_parameter/base_color = Color(0.75, 0.75, 0.76, 1)
-shader_parameter/crater_color = Color(0.44, 0.44, 0.45, 1)
-shader_parameter/highlight_color = Color(0.89, 0.89, 0.9, 1)
+shader_parameter/tile_cells = 32.0
 
 [node name="PlanetSurface" type="Node2D"]
 script = ExtResource("1")
@@ -97,12 +96,16 @@ theme_override_constants/outline_size = 4
 text = "FLEET HOLD"
 
 [node name="PlanetNameLabel" type="Label" parent="UI"]
-offset_left = 24
-offset_top = 156
+mouse_filter = 2
+offset_left = 400
+offset_top = 40
 offset_right = 696
-offset_bottom = 282
+offset_bottom = 148
 text = ""
-horizontal_alignment = 1
+horizontal_alignment = 2
+vertical_alignment = 0
+autowrap_mode = 2
+theme_override_font_sizes/font_size = 30
 theme_override_colors/font_color = Color(0.08, 0.08, 0.11, 1)
 theme_override_colors/font_outline_color = Color(0.95, 0.95, 0.96, 0.85)
 theme_override_constants/outline_size = 5
diff --git a/ResourceReadout.gd b/ResourceReadout.gd
index c88433f..a2f6d97 100644
--- a/ResourceReadout.gd
+++ b/ResourceReadout.gd
@@ -61,6 +61,26 @@ func _ready() -> void:
 
 		y += ROW_HEIGHT
 
+	# Stop understating our own extent. The rows are drawn by child nodes,
+	# which happily paint outside this Control's rect, so the scene-authored
+	# height stayed at its original guess no matter how many rows appeared.
+	size.y = rows_height()
+
+
+# How tall the rows are, derived from the live resource list rather than from
+# whatever _ready() happened to have built. That matters: _ready() runs in
+# scene-tree order, so a sibling laying itself out relative to this readout
+# (BuildController._seat_hud_columns) can legitimately ask BEFORE this node
+# has built anything, and a cached height would answer zero.
+func rows_height() -> float:
+	return float(GameState.resource_types().size()) * ROW_HEIGHT
+
+
+# Bottom edge of the rows in this Control's parent space - the line anything
+# stacked below the readout has to clear.
+func content_bottom() -> float:
+	return position.y + rows_height()
+
 
 func _add_glyph(resource_type: String, at: Vector2) -> void:
 	var glyph: ResourceGlyph = ResourceGlyph.new()
diff --git a/Ship.gd b/Ship.gd
index 074c6b4..08baa0c 100644
--- a/Ship.gd
+++ b/Ship.gd
@@ -13,7 +13,15 @@ const VESSEL_DEFINITIONS = preload("res://VesselDefinitions.gd")
 var definition: Resource
 var glow_color: Color = Color(0.25, 0.85, 1.0)
 var core_color: Color = Color.WHITE
+# The ship's TRUE world velocity - what `position` is actually integrated
+# from, and the single source of truth for how fast this vessel is moving.
+# Nothing else may contribute motion; see the note in _physics_process.
 var velocity: Vector2 = Vector2.ZERO
+# The velocity of this ship's formation SLOT (the fleet anchor's own travel).
+# Fed forward into the steering below rather than added on top of it: matching
+# the slot's speed is most of the job of holding formation, so supplying it
+# directly leaves `velocity` free to be a small correction and lets the ship
+# sit in its slot with no steady-state lag and no teleporting.
 var fleet_velocity: Vector2 = Vector2.ZERO
 var move_target: Vector2
 
@@ -109,22 +117,47 @@ func _physics_process(delta: float) -> void:
 	# "snaps onto its slot" formation tightness at any boost level that
 	# 1.0x already has.
 	var boost: float = GameState.fleet_speed_multiplier
+	var effective_acceleration: float = acceleration * boost
 	var to_target: Vector2 = move_target - position
 	var distance: float = to_target.length()
-	if distance <= arrive_radius * boost:
+
+	# Snap only when the slot is STANDING STILL. A stationary target is the
+	# one case where converging asymptotically would leave a permanent
+	# sub-pixel residue, and settling exactly is what "the fleet has arrived"
+	# means everywhere else in the game. While the slot is moving the ship
+	# steers continuously instead - a snap there would be a teleport, which
+	# is what used to make `velocity` read zero for a ship that was in fact
+	# travelling at cruise speed, and that lie is what the whole
+	# stop()/fleet_velocity bookkeeping tangle existed to paper over.
+	if fleet_velocity == Vector2.ZERO and distance <= arrive_radius * boost:
 		position = move_target
 		velocity = Vector2.ZERO
 	else:
-		var effective_acceleration: float = acceleration * boost
-		var braking_speed: float = sqrt(2.0 * effective_acceleration * distance)
-		var desired_speed: float = min(max_speed * boost, braking_speed)
-		var desired_velocity: Vector2 = to_target.normalized() * desired_speed
+		# Feed-forward plus correction. The ship aims to travel at its slot's
+		# velocity, plus whatever extra closes the gap to the slot - so
+		# holding formation costs no error, and `velocity` stays the ship's
+		# real motion rather than a residual that has to be added to
+		# something else to mean anything.
+		var correction: Vector2 = Vector2.ZERO
+		if distance > 0.001:
+			var braking_speed: float = sqrt(2.0 * effective_acceleration * distance)
+			correction = to_target.normalized() * min(max_speed * boost, braking_speed)
+		var desired_velocity: Vector2 = fleet_velocity + correction
+		# HARD BOUND on how fast any single vessel may travel, applied to the
+		# total and re-applied every tick. Feed-forward plus correction can
+		# ask for more than a vessel can actually fly, and without this the
+		# excess was free speed: a ship that had been handed a large velocity
+		# kept it, decaying only at `acceleration`. Clamping the REQUEST is
+		# not enough - the clamp has to sit on the integrated result, so no
+		# sequence of commands can leave a vessel travelling faster than its
+		# own top speed.
+		desired_velocity = desired_velocity.limit_length(max_speed * boost)
 		velocity = velocity.move_toward(desired_velocity, effective_acceleration * delta)
+		velocity = velocity.limit_length(max_speed * boost)
 		position += velocity * delta
 
-	var motion: Vector2 = velocity + fleet_velocity
-	if motion.length() > 8.0:
-		var target_angle: float = motion.angle() + PI / 2.0
+	if velocity.length() > 8.0:
+		var target_angle: float = velocity.angle() + PI / 2.0
 		rotation = lerp_angle(rotation, target_angle, rotation_speed * delta)
 
 
diff --git a/lunar_surface.gdshader b/lunar_surface.gdshader
index a1158ee..9f42999 100644
--- a/lunar_surface.gdshader
+++ b/lunar_surface.gdshader
@@ -25,6 +25,14 @@ shader_type canvas_item;
 // a thin bright rim wedge through the middle of the merged basin. The
 // second-nearest distance is tracked purely to detect that case and fade
 // the rim out there - see the note further down.
+//
+// This runs on EVERY pixel of a fullscreen rect on a phone, so it is the
+// single most expensive thing in the surface scene and the subject of
+// Forgejo #68 ("the moon game is a bit slow"). The three optimizations
+// that brought it down - a bounded 3x3 scan, one hash per cell instead of
+// three, and one sqrt per pixel instead of one per sample - are each
+// justified at the point they appear below. Time it with
+//   bash tests/profile_shader.sh res://lunar_surface.gdshader
 
 uniform vec2 camera_cell = vec2(0.0, 0.0);
 uniform vec2 camera_frac = vec2(0.0, 0.0);
@@ -46,33 +54,62 @@ uniform vec4 highlight_color : source_color = vec4(0.89, 0.89, 0.90, 1.0);
 //       cuts appear in this grayscale output the FIELD is at fault, and if
 //       it is smooth the field is fine and the SHADING is at fault.
 uniform float debug_mode = 0.0;
+// Width of the repeating tile, in cells. The crater field is made PERIODIC
+// with this period (see the wrap in the loop), which is what lets
+// LunarBackground.gd bake one square of it into a texture and then scroll
+// that texture forever with repeat wrapping, instead of re-deriving the
+// field per pixel per frame. Set from LunarBackground.TILE_CELLS, which is
+// the single source of truth shared with lunar_tiled.gdshader.
+uniform float tile_cells = 32.0;
+// BAKE MODE. 0 = normal camera-relative sampling for direct display.
+// Above zero, UV is mapped straight onto [0, tile_cells] instead, so
+// rendering this shader to a square SubViewport produces exactly one period
+// of the field - the texture the runtime shader then samples.
+uniform float bake_cells = 0.0;
 
 const vec2 LIGHT_DIR = vec2(-0.6, -0.8);
 const float MIN_RADIUS = 0.16;
+// MUST stay below 1.0. The 3x3 scan below is only correct because a crater
+// cannot reach out of its own cell's immediate neighbourhood; see the long
+// note at the loop. tests/test_lunar_field.gd asserts this bound directly
+// against the shader source so it cannot drift unnoticed.
 const float MAX_RADIUS = 0.38;
-// Sentinel for "this cell holds no crater". Must stay well inside mediump
-// range (max ~65504) so it can never become +Inf - see the note in the
-// loop. Only needs to exceed the largest real normalized distance (~18).
-const float MISS_DISTANCE = 1000.0;
+// Sentinel for "this cell holds no crater", in SQUARED normalized units to
+// match the loop. Must stay well inside mediump range (max ~65504) so it
+// can never become +Inf - see the note in the loop. Only needs to exceed
+// the largest real squared normalized distance, which for a 3x3 scan is
+// (2.83 cells / 0.16 min radius)^2 ~= 313.
+const float MISS_DISTANCE_SQ = 10000.0;
+// Loop-carried initial value. Above any real value INCLUDING one carrying
+// the miss sentinel (~10313), so a pixel whose whole neighbourhood is
+// empty still leaves the "winning" offset populated with something finite.
+const float START_DISTANCE_SQ = 20000.0;
+
+// One hash call yields all four values a cell needs (crater centre x/y,
+// whether the cell holds a crater at all, and its radius). The previous
+// version called two different hashes three times per cell with different
+// constant offsets, which was three quarters of the loop body's arithmetic
+// for no extra information - a single hash with four independent output
+// lanes decorrelates just as well.
+//
+// Multipliers chosen for precision safety on mobile GPUs: they are all
+// < 1, so every intermediate stays small no matter how large the cell
+// index gets. An earlier version multiplied by ~123/456 first, which lands
+// the intermediate in the thousands where a mobile float loses its
+// fractional bits entirely. (Standard "hash without sine" formulation,
+// Dave Hoskins.)
+vec4 hash42(vec2 p) {
+	vec4 p4 = fract(vec4(p.xyxy) * vec4(0.1031, 0.1030, 0.0973, 0.1099));
+	p4 += dot(p4, p4.wzxy + 33.33);
+	return fract((p4.xxyz + p4.yzzw) * p4.zywx);
+}
 
-// Hash pair chosen for precision safety on mobile GPUs. The previous
-// version multiplied the cell coordinate by ~123/456 before fract(), which
-// lands the intermediate in the thousands where a mobile float loses its
-// fractional bits entirely. These multipliers are all < 1, so every
-// intermediate stays small no matter how large the cell index gets.
-// (Standard "hash without sine" formulation, Dave Hoskins.)
 float hash21(vec2 p) {
 	vec3 p3 = fract(vec3(p.xyx) * 0.1031);
 	p3 += dot(p3, p3.yzx + 33.33);
 	return fract((p3.x + p3.y) * p3.z);
 }
 
-vec2 hash22(vec2 p) {
-	vec3 p3 = fract(vec3(p.xyx) * vec3(0.1031, 0.1030, 0.0973));
-	p3 += dot(p3, p3.yzx + 33.33);
-	return fract((p3.xx + p3.yz) * p3.zy);
-}
-
 void fragment() {
 	vec2 screen_px = UV * viewport_size;
 	vec2 centered = screen_px - viewport_size * 0.5;
@@ -92,11 +129,18 @@ void fragment() {
 	// calling floor(x) and fract(x) separately lets the GPU round the two
 	// evaluations differently, which right at a cell boundary makes them
 	// disagree by a full cell and snaps the sampled point one cell sideways.
-	vec2 rel = camera_frac + centered * (camera_zoom / cell_size);
+	//
+	// In bake mode none of that applies: the target is one tile of the field
+	// in isolation, so UV maps directly onto [0, bake_cells] and there is no
+	// camera in the picture at all.
+	bool baking = bake_cells > 0.0;
+	vec2 rel = baking
+		? UV * bake_cells
+		: camera_frac + centered * (camera_zoom / cell_size);
 	vec2 cell_rel = floor(rel);
 	vec2 local = rel - cell_rel;
 	// Absolute cell index, used only for hashing. Built from exact integers.
-	vec2 cell = camera_cell + cell_rel;
+	vec2 cell = baking ? cell_rel : camera_cell + cell_rel;
 
 	// Single scalar field: normalized distance to the nearest crater.
 	// < 1.0 means this pixel is inside that crater; 1.0 is exactly on its
@@ -110,22 +154,49 @@ void fragment() {
 	// through the middle of what should read as one merged depression.
 	// A pixel in that region is inside BOTH craters, i.e. second_nearest is
 	// also < 1.0 - which is precisely the condition to fade the rim out.
-	float nearest = MISS_DISTANCE;
-	float second_nearest = MISS_DISTANCE;
-	vec2 nearest_dir = vec2(0.0, 1.0);
+	//
+	// Tracked SQUARED, and square-rooted once at the end. Ordering is
+	// unchanged by squaring (both sides are non-negative), so the same
+	// crater wins - but this turns one sqrt per sample into two per pixel,
+	// and sqrt is one of the more expensive things a fragment shader can
+	// ask for.
+	float nearest_sq = START_DISTANCE_SQ;
+	float second_nearest_sq = START_DISTANCE_SQ;
+	vec2 nearest_offset = vec2(0.0, 1.0);
 
-	// 5x5 rather than 3x3. A crater's radius is at most MAX_RADIUS cells,
-	// so in theory 3x3 covers every crater that could possibly reach this
-	// pixel - but on-device, craters were still being clipped exactly at
-	// cell boundaries, which means some crater's influence was reaching
-	// further than the scan did (e.g. a hash returning a value outside its
-	// nominal range on that GPU, inflating a radius). Scanning two cells
-	// out costs more samples but makes the clip impossible to reach even
-	// if a radius comes out several times larger than intended.
-	for (int dx = -2; dx <= 2; dx++) {
-		for (int dy = -2; dy <= 2; dy++) {
+	// 3x3 is provably sufficient, and provably so only because of the two
+	// clamps in the loop body. A crater's centre is clamped into its own
+	// cell and its radius is clamped to at most MAX_RADIUS (0.38) cells, so
+	// the furthest a crater can reach past its own cell is 0.38 cells. This
+	// pixel's `local` lies in [0,1], so a crater two cells out is at least
+	// 1.0 cells away - a normalized distance of at least 1/0.38 = 2.6,
+	// which is past every threshold used below (the floor fades out by 0.9,
+	// the rim band by 1.0, and the overlap suppression saturates at 1.15).
+	// Such a crater therefore cannot change a single pixel of the output.
+	//
+	// This replaces an earlier 5x5 scan. That width was not chosen from the
+	// geometry - 3x3 was already the geometric answer - but as insurance
+	// against craters that were observed clipping at cell boundaries
+	// on-device, which meant some crater's influence was reaching further
+	// than its nominal radius allowed, e.g. a hash returning a value outside
+	// [0,1] on that GPU and extrapolating mix() into a huge radius. Clamping
+	// both the radius AND the centre fixes that at the source and makes the
+	// bound above hold no matter what the hash returns, so paying for 25
+	// samples per pixel to hide a driver quirk is no longer necessary.
+	// tests/test_lunar_field.gd checks the two scans agree exactly.
+	for (int dx = -1; dx <= 1; dx++) {
+		for (int dy = -1; dy <= 1; dy++) {
 			vec2 offset = vec2(float(dx), float(dy));
-			highp vec2 neighbor_cell = cell + offset;
+			// Wrapping the cell index before hashing is the entire trick that
+			// makes the field tileable: cell N and cell N + tile_cells hash
+			// identically, so the pattern repeats exactly with that period.
+			// It works on a Worley field specifically because the scan only
+			// ever reads immediate neighbours - wrap those consistently and
+			// the seam is not merely hidden, it does not exist. GLSL mod()
+			// returns a non-negative result for a positive divisor, so
+			// negative cell indices wrap correctly too.
+			highp vec2 neighbor_cell = mod(cell + offset, tile_cells);
+			vec4 h = hash42(neighbor_cell);
 
 			// Cells without a crater are pushed far away rather than
 			// branched around, keeping the loop body uniform. NOTE the
@@ -134,32 +205,45 @@ void fragment() {
 			// becomes +Inf there, and (1.0 - has_crater) * Inf evaluates to
 			// 0 * Inf = NaN for every cell that DOES hold a crater - which
 			// compares false against everything and would silently discard
-			// every crater. MISS_DISTANCE only has to beat the largest real
-			// normalized distance (~2.9 cells / 0.16 min radius ~= 18).
-			float has_crater = step(0.35, hash21(neighbor_cell + vec2(41.0, 5.0)));
-			vec2 crater_center = offset + hash22(neighbor_cell);
+			// every crater.
+			float has_crater = step(0.35, h.z);
+			// clamp() on both of these is what bounds a crater's reach to
+			// its own cell plus MAX_RADIUS, which is what lets the scan
+			// above be 3x3. Without them a driver returning a hash outside
+			// [0,1] could place a centre, or inflate a radius, far enough to
+			// reach past the scan - which is exactly the clipping that was
+			// seen on-device.
+			vec2 crater_center = offset + clamp(h.xy, 0.0, 1.0);
+			float radius = clamp(mix(MIN_RADIUS, MAX_RADIUS, h.w), MIN_RADIUS, MAX_RADIUS);
+
 			vec2 to_sample = local - crater_center;
-			float dist = length(to_sample);
-			// clamp() guards against a hash landing outside [0,1] on some
-			// driver and extrapolating mix() into a huge radius.
-			float radius = clamp(mix(MIN_RADIUS, MAX_RADIUS, hash21(neighbor_cell + vec2(9.0, 2.0))), MIN_RADIUS, MAX_RADIUS);
+			float normalized_sq = dot(to_sample, to_sample) / (radius * radius)
+				+ (1.0 - has_crater) * MISS_DISTANCE_SQ;
 
-			float normalized = dist / radius + (1.0 - has_crater) * MISS_DISTANCE;
-
-			if (normalized < nearest) {
-				second_nearest = nearest;
-				nearest = normalized;
-				// Direction from the winning crater's centre to this pixel,
-				// used for the rim's light/shadow split. Taken from the SAME
-				// crater that won the distance test, so the shading can never
-				// describe one crater while the floor describes another.
-				nearest_dir = dist > 0.0001 ? to_sample / dist : vec2(0.0, 1.0);
-			} else if (normalized < second_nearest) {
-				second_nearest = normalized;
+			if (normalized_sq < nearest_sq) {
+				second_nearest_sq = nearest_sq;
+				nearest_sq = normalized_sq;
+				// Offset from the winning crater's centre to this pixel,
+				// kept so the rim's light/shadow split can be derived from
+				// the SAME crater that won the distance test - the shading
+				// can then never describe one crater while the floor
+				// describes another.
+				nearest_offset = to_sample;
+			} else if (normalized_sq < second_nearest_sq) {
+				second_nearest_sq = normalized_sq;
 			}
 		}
 	}
 
+	float nearest = sqrt(nearest_sq);
+	float second_nearest = sqrt(second_nearest_sq);
+	// normalize() would divide by zero for a pixel sitting exactly on a
+	// crater centre; the guard keeps that pixel's rim term merely arbitrary
+	// rather than NaN. It is deep inside the floor, where the rim band is
+	// zero anyway.
+	float offset_length = length(nearest_offset);
+	vec2 nearest_dir = offset_length > 0.0001 ? nearest_offset / offset_length : vec2(0.0, 1.0);
+
 	vec2 light_dir = normalize(LIGHT_DIR);
 	float facing = dot(nearest_dir, light_dir);
 
@@ -188,8 +272,14 @@ void fragment() {
 	// can visibly "step" into faint bands on real hardware. A small random
 	// jitter well under one visible step breaks the stepping up without
 	// being perceptible as noise.
-	float dither = (hash21(screen_px + vec2(7.0, 13.0)) - 0.5) / 128.0;
-	color += vec3(dither);
+	// Skipped when baking: dither is a per-SCREEN-pixel jitter, and baking it
+	// would freeze the noise into the texture, where magnification smears it
+	// into visible blotches and tiling repeats it. lunar_tiled.gdshader
+	// applies the identical term live instead, which is where it belongs.
+	if (!baking) {
+		float dither = (hash21(screen_px + vec2(7.0, 13.0)) - 0.5) / 128.0;
+		color += vec3(dither);
+	}
 
 	// Diagnostic checkerboard: alternate cells tinted, plus a bright line
 	// right at each cell edge. Makes the grid unmistakable in a screenshot.
diff --git a/lunar_tiled.gdshader b/lunar_tiled.gdshader
new file mode 100644
index 0000000..1574c85
--- /dev/null
+++ b/lunar_tiled.gdshader
@@ -0,0 +1,79 @@
+shader_type canvas_item;
+
+// The lunar backdrop as it is actually drawn every frame: one texture fetch
+// plus a dither, and nothing else.
+//
+// Forgejo #68. lunar_surface.gdshader derives the crater field procedurally,
+// which costs a 9-sample Worley scan on every pixel of a fullscreen rect,
+// every frame, forever - and it recomputes the exact same answer each time,
+// because the field is a fixed function of world position. So it is
+// evaluated ONCE, into a square texture covering one period of the field
+// (LunarBackground.gd does the bake at scene load), and this shader scrolls
+// that texture with repeat wrapping. The canvas stays infinite; the per-
+// frame cost stops scaling with how complicated the field is.
+//
+// Two things pay for that, both stated plainly because they are real:
+//
+//   1. The field REPEATS, every tile_cells * cell_size world units. It is
+//      seamless (lunar_surface.gdshader wraps the cell index before hashing,
+//      so the periodicity is exact rather than blended), but a player who
+//      flies far enough passes the same crater arrangement again. Lunar
+//      regolith is about the most forgiving possible content for that: no
+//      landmarks, no horizon, no orientation cues, nothing to anchor a
+//      memory of "I have seen this crater before" to.
+//   2. The texture has a fixed resolution, so zooming in past its native
+//      density softens the craters rather than resolving finer ones. The
+//      field is smooth gradients by construction - the sharpest thing in it
+//      is the rim band, and that still spans several texels - so bilinear
+//      magnification reproduces it closely instead of showing blocks.
+//
+// Mipmaps handle the other direction (zooming out), which is where a
+// high-frequency crater field would otherwise alias into shimmer.
+
+uniform sampler2D field_texture : filter_linear_mipmap, repeat_enable;
+uniform vec2 camera_cell = vec2(0.0, 0.0);
+uniform vec2 camera_frac = vec2(0.0, 0.0);
+uniform float camera_zoom = 1.0;
+uniform vec2 viewport_size = vec2(720.0, 1280.0);
+uniform float cell_size = 220.0;
+uniform float tile_cells = 32.0;
+
+float hash21(vec2 p) {
+	vec3 p3 = fract(vec3(p.xyx) * 0.1031);
+	p3 += dot(p3, p3.yzx + 33.33);
+	return fract((p3.x + p3.y) * p3.z);
+}
+
+void fragment() {
+	vec2 screen_px = UV * viewport_size;
+	vec2 centered = screen_px - viewport_size * 0.5;
+
+	// Same camera-relative construction as the procedural shader, and for
+	// the same reason: an absolute world position reaches the tens of
+	// thousands, where a mobile float has lost the fractional bits this
+	// needs. camera_cell arrives ALREADY WRAPPED into [0, tile_cells) -
+	// LunarBackground.gd does that wrap in GDScript's double precision, so
+	// the large number never enters the shader at all.
+	vec2 rel = camera_frac + centered * (camera_zoom / cell_size);
+	vec2 uv = (camera_cell + rel) / tile_cells;
+
+	// repeat_enable does the wrapping, so uv running outside [0,1] is not
+	// merely tolerated, it is the mechanism.
+	vec3 color = texture(field_texture, uv).rgb;
+
+	// Tiny per-pixel dither to mask 8-bit colour-quantization banding: the
+	// crater shading is a smooth gradient over a fairly large area, which
+	// can visibly "step" into faint bands on real hardware. A small random
+	// jitter well under one visible step breaks the stepping up without
+	// being perceptible as noise. Doubly needed here - the baked texture is
+	// itself 8-bit, so it quantizes the gradient a second time.
+	//
+	// Deliberately keyed to the SCREEN pixel, not the world position: it has
+	// to stay fixed to the display or it turns into crawling noise as the
+	// camera moves, and it must not be baked into the tile or it would
+	// repeat along with everything else.
+	float dither = (hash21(screen_px + vec2(7.0, 13.0)) - 0.5) / 128.0;
+	color += vec3(dither);
+
+	COLOR = vec4(color, 1.0);
+}
diff --git a/lunar_tiled.gdshader.uid b/lunar_tiled.gdshader.uid
new file mode 100644
index 0000000..03c7ea0
--- /dev/null
+++ b/lunar_tiled.gdshader.uid
@@ -0,0 +1 @@
+uid://dmmdpa3pmr8g
diff --git a/tests/_profile_surface_shader.gd b/tests/_profile_surface_shader.gd
new file mode 100644
index 0000000..15a7868
--- /dev/null
+++ b/tests/_profile_surface_shader.gd
@@ -0,0 +1,106 @@
+extends SceneTree
+
+# Not a test - a stopwatch for a fullscreen background shader, in the same
+# spirit as _profile_startup.gd but aimed at the FRAGMENT side instead of
+# scene setup. Forgejo #68 ("the moon game is a bit slow").
+#
+# Renders nothing but one fullscreen ColorRect carrying the given shader, so
+# the frame time is essentially pure per-pixel shader cost with no gameplay,
+# UI or draw calls mixed in. Run it via tests/profile_shader.sh, which
+# supplies Xvfb + Mesa softpipe exactly like screenshot.sh does.
+#
+# Softpipe is a pure-C rasterizer, not the phone's GPU, so the ABSOLUTE
+# numbers mean nothing. What it measures well is RELATIVE per-fragment ALU
+# cost between two versions of the same shader: softpipe executes the
+# fragment program per pixel on the CPU, so halving the arithmetic shows up
+# as roughly half the frame time.
+#
+# TWO THINGS WILL MISLEAD YOU IF YOU READ THE RAW NUMBER.
+#
+# 1. There is a FLOOR. A shader that does nothing but assign a constant
+#    colour still costs ~657 ms/frame at 720x1280 here, which is softpipe's
+#    own per-pixel overhead. Subtract it before comparing, or a shader that
+#    got 20x cheaper will look like it only got 2x cheaper.
+#
+# 2. It cannot price a TEXTURE FETCH against arithmetic. Softpipe does
+#    filtering and mip selection in CPU code, so a fetch measures as
+#    expensive here; real GPUs - mobile ones especially - run it on
+#    dedicated hardware where it is close to free. Trading arithmetic for a
+#    lookup is exactly the kind of change this harness will report backwards.
+#    Use it to compare arithmetic against arithmetic, and nothing else.
+#
+# Args (after `--`): <shader_res_path> [timed_frames] [warmup_frames]
+
+var shader_path: String
+var timed_frames: int = 30
+var warmup_frames: int = 10
+var frames: int = 0
+var rect: ColorRect
+var start_usec: int = 0
+
+
+func _initialize() -> void:
+	var args: PackedStringArray = OS.get_cmdline_user_args()
+	if args.is_empty():
+		printerr("usage: -- <shader_res_path> [timed_frames] [warmup_frames]")
+		quit(1)
+		return
+	shader_path = args[0]
+	if args.size() >= 2:
+		timed_frames = int(args[1])
+	if args.size() >= 3:
+		warmup_frames = int(args[2])
+
+	var shader: Shader = load(shader_path)
+	if shader == null:
+		printerr("could not load shader: %s" % shader_path)
+		quit(1)
+		return
+
+	var material := ShaderMaterial.new()
+	material.shader = shader
+
+	var layer := CanvasLayer.new()
+	layer.layer = -10
+	root.add_child(layer)
+
+	rect = ColorRect.new()
+	rect.material = material
+	rect.anchor_right = 1.0
+	rect.anchor_bottom = 1.0
+	rect.size = root.get_visible_rect().size
+	layer.add_child(rect)
+
+
+func _process(_delta: float) -> bool:
+	# Move the camera every frame. A static camera would let a driver skip
+	# redundant uniform uploads and would only ever exercise one crater
+	# layout; drifting keeps the measurement honest and representative of
+	# actually flying around.
+	var t: float = float(frames) * 0.05
+	var p: Vector2 = Vector2(cos(t), sin(t)) * 40.0
+	var cell := Vector2(floor(p.x), floor(p.y))
+	rect.material.set_shader_parameter("camera_cell", cell)
+	rect.material.set_shader_parameter("camera_frac", p - cell)
+	rect.material.set_shader_parameter("camera_zoom", 1.0)
+	rect.material.set_shader_parameter("viewport_size", root.get_visible_rect().size)
+
+	frames += 1
+	# Shaders compile on first use and the first frames carry that cost, so
+	# start the clock only once the pipeline is warm.
+	if frames == warmup_frames:
+		start_usec = Time.get_ticks_usec()
+		return false
+	if frames < warmup_frames + timed_frames:
+		return false
+
+	var span_usec: int = Time.get_ticks_usec() - start_usec
+	var per_frame_ms: float = float(span_usec) / 1000.0 / float(timed_frames)
+	var px: Vector2 = root.get_visible_rect().size
+	print("SHADER_PROFILE: %s" % shader_path)
+	print("  viewport      : %dx%d (%d px)" % [px.x, px.y, int(px.x * px.y)])
+	print("  frames timed  : %d (after %d warmup)" % [timed_frames, warmup_frames])
+	print("  per frame     : %.1f ms" % per_frame_ms)
+	print("  per megapixel : %.1f ms" % (per_frame_ms / (px.x * px.y / 1000000.0)))
+	quit(0)
+	return true
diff --git a/tests/_profile_surface_shader.gd.uid b/tests/_profile_surface_shader.gd.uid
new file mode 100644
index 0000000..73e9418
--- /dev/null
+++ b/tests/_profile_surface_shader.gd.uid
@@ -0,0 +1 @@
+uid://dgg7cnpiq2y58
diff --git a/tests/_setup_editor_load_panel_preview.gd.uid b/tests/_setup_editor_load_panel_preview.gd.uid
new file mode 100644
index 0000000..f81e4d7
--- /dev/null
+++ b/tests/_setup_editor_load_panel_preview.gd.uid
@@ -0,0 +1 @@
+uid://ckltesr471lqy
diff --git a/tests/profile_shader.sh b/tests/profile_shader.sh
new file mode 100644
index 0000000..3a57e52
--- /dev/null
+++ b/tests/profile_shader.sh
@@ -0,0 +1,34 @@
+#!/data/data/com.termux/files/usr/bin/bash
+# Times a fullscreen background shader's per-pixel cost. Same Xvfb + Mesa
+# softpipe rig as screenshot.sh (see the long note there about llvmpipe
+# crashing with SIGILL in this environment), because a fragment shader can
+# only be timed if something actually rasterizes it - --headless renders
+# nothing at all.
+#
+# Softpipe is a CPU rasterizer, so treat the numbers as RELATIVE only:
+# comparing two versions of the same shader is meaningful, comparing against
+# a phone's frame budget is not.
+#
+# Usage: bash tests/profile_shader.sh <shader_res_path> [timed_frames] [warmup] [WxH]
+# Example: bash tests/profile_shader.sh res://lunar_surface.gdshader 30 10 720x1280
+
+set -e
+PROJECT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+GODOT_BIN="/root/Godot_v4.7.1-stable_linux.arm64"
+
+SHADER_PATH="${1:?usage: profile_shader.sh <shader_res_path> [timed_frames] [warmup] [WxH]}"
+TIMED_FRAMES="${2:-30}"
+WARMUP_FRAMES="${3:-10}"
+RESOLUTION="${4:-720x1280}"
+
+proot-distro login ubuntu -- bash -c "
+pkill -x Xvfb >/dev/null 2>&1 || true
+rm -f /tmp/.X99-lock /tmp/.X11-unix/X99
+Xvfb :99 -screen 0 ${RESOLUTION}x24 &
+XVFB_PID=\$!
+trap 'kill \$XVFB_PID >/dev/null 2>&1 || true' EXIT
+sleep 2
+mkdir -p /tmp/xdgrt && chmod 700 /tmp/xdgrt
+cd '$PROJECT_DIR'
+DISPLAY=:99 XDG_RUNTIME_DIR=/tmp/xdgrt GALLIUM_DRIVER=softpipe '$GODOT_BIN' --audio-driver Dummy --rendering-driver opengl3 --rendering-method gl_compatibility --resolution '$RESOLUTION' -s res://tests/_profile_surface_shader.gd -- '$SHADER_PATH' '$TIMED_FRAMES' '$WARMUP_FRAMES'
+"
diff --git a/tests/test_enemy_detection_range.gd.uid b/tests/test_enemy_detection_range.gd.uid
new file mode 100644
index 0000000..2500c16
--- /dev/null
+++ b/tests/test_enemy_detection_range.gd.uid
@@ -0,0 +1 @@
+uid://dekjmrvv0baqy
diff --git a/tests/test_fleet_speed_bounded.gd b/tests/test_fleet_speed_bounded.gd
new file mode 100644
index 0000000..3b69888
--- /dev/null
+++ b/tests/test_fleet_speed_bounded.gd
@@ -0,0 +1,196 @@
+extends SceneTree
+
+# Headless gameplay test: run with
+#   godot --headless -s res://tests/test_fleet_speed_bounded.gd
+# A reported movement bug: rotating the fleet and spamming a direction let
+# vessels fall out of sync and fly at wildly high speeds - "speed of an
+# individual ship is not bounded".
+#
+# The cause was in Fleet.stop(), which compensated for Ship.velocity reading
+# zero during cruise by doing `ship.velocity += ship.fleet_velocity`. That is
+# an accumulator: each release added a whole cruise velocity, the next steer
+# refilled fleet_velocity, and tapping faster than `acceleration` could bleed
+# it off stacked them without limit. Ships desynced because each bled off at
+# a rate set by its own distance to its slot.
+#
+# Covers:
+#   A. no vessel ever exceeds its own top speed, however hard the direction
+#      is spammed - the property that was actually violated
+#   B. spamming cannot outrun an honestly-held stick: the fleet covers no
+#      more ground than cruising for the same time would
+#   C. the same holds while the formation is being pivoted, which is the
+#      case the report named
+#   D. ships stay in sync with each other rather than fanning out
+
+var game_state: Node
+var main: Node
+var fleet: Node
+var stage: int = 0
+var elapsed: float = 0.0
+var fastest_seen: float = 0.0
+var worst_spread: float = 0.0
+var start_centroid: Vector2 = Vector2.ZERO
+var spam_toggle: bool = false
+var pivot_step: int = 0
+var honest_distance: float = 0.0
+
+const SPAM_TIME: float = 3.0
+# Every ship in the test fleet is an interceptor, so one limit covers them
+# all. Two percent of slack absorbs the single-tick overshoot inherent in
+# integrating at a finite step; the bug being caught overshot by multiples,
+# not by percents.
+const SPEED_TOLERANCE: float = 1.02
+
+
+func _initialize() -> void:
+	game_state = root.get_node("GameState")
+	game_state.buildings.clear()
+	game_state.extractors.clear()
+	game_state.transporters.clear()
+	game_state.stored_vessels.clear()
+	game_state.reset_progression()
+	main = load("res://Main.tscn").instantiate()
+	root.add_child(main)
+	fleet = main.get_node("Fleet")
+
+
+func _process(delta: float) -> bool:
+	elapsed += delta
+	match stage:
+		0:
+			if elapsed < 0.2:
+				return false
+			main.get_node("EnemySpawner").set_process(false)
+			main.get_node("AsteroidField").set_process(false)
+			fleet.spawn_ships(4, Vector2.ZERO)
+
+			# --- reference: what holding the stick honestly achieves --------
+			start_centroid = fleet.get_centroid()
+			fleet.move_in_direction(Vector2(1.0, 0.0))
+			elapsed = 0.0
+			stage = 1
+			return false
+		1:
+			if elapsed < SPAM_TIME:
+				_watch_speeds()
+				return false
+			honest_distance = fleet.get_centroid().distance_to(start_centroid)
+			print("held steady for %.1fs: travelled %.1f, fastest vessel %.1f" \
+				% [SPAM_TIME, honest_distance, fastest_seen])
+			if not _check_speed_bound("while simply holding a direction"):
+				return true
+			fleet.stop()
+			fastest_seen = 0.0
+			elapsed = 0.0
+			stage = 2
+			return false
+		2:
+			# Let the coast-to-rest finish so the spam leg starts from the
+			# same standing start the honest leg did.
+			if elapsed < 1.0:
+				return false
+			start_centroid = fleet.get_centroid()
+			elapsed = 0.0
+			stage = 3
+			return false
+		3:
+			# --- A + B. tap the same direction as fast as frames allow ------
+			spam_toggle = not spam_toggle
+			if spam_toggle:
+				fleet.move_in_direction(Vector2(1.0, 0.0))
+			else:
+				fleet.stop()
+			_watch_speeds()
+			if elapsed < SPAM_TIME:
+				return false
+			var spam_distance: float = fleet.get_centroid().distance_to(start_centroid)
+			print("spammed for %.1fs: travelled %.1f, fastest vessel %.1f" \
+				% [SPAM_TIME, spam_distance, fastest_seen])
+			if not _check_speed_bound("while spamming a direction"):
+				return true
+			# Tapping releases the stick half the time, so it should cover
+			# LESS ground than holding it - certainly not more.
+			if spam_distance > honest_distance * 1.1:
+				return _fail_now("spamming a direction covered %.1f against %.1f for simply holding it - tapping is faster than flying" \
+					% [spam_distance, honest_distance])
+			fleet.stop()
+			fastest_seen = 0.0
+			elapsed = 0.0
+			stage = 4
+			return false
+		4:
+			if elapsed < 1.0:
+				return false
+			start_centroid = fleet.get_centroid()
+			elapsed = 0.0
+			stage = 5
+			return false
+		5:
+			# --- C + D. spam the direction WHILE pivoting the formation -----
+			# The reported case. A pivot re-seats every slot at once, so this
+			# is where ships are most able to fall out of step with one
+			# another.
+			spam_toggle = not spam_toggle
+			if spam_toggle:
+				fleet.move_in_direction(Vector2(1.0, 0.0))
+			else:
+				fleet.stop()
+			pivot_step += 1
+			_pivot_formation(PI / 2.0 if pivot_step % 2 == 0 else -PI / 2.0)
+			_watch_speeds()
+			if elapsed < SPAM_TIME:
+				return false
+			var pivot_distance: float = fleet.get_centroid().distance_to(start_centroid)
+			print("spammed with pivots for %.1fs: travelled %.1f, fastest vessel %.1f, worst pair spread %.1f" \
+				% [SPAM_TIME, pivot_distance, fastest_seen, worst_spread])
+			if not _check_speed_bound("while spamming a direction and pivoting"):
+				return true
+			if pivot_distance > honest_distance * 1.1:
+				return _fail_now("spamming with pivots covered %.1f against %.1f for simply holding a direction" \
+					% [pivot_distance, honest_distance])
+			# Ships must remain a fleet. The formation is a wedge a couple of
+			# hundred units across; a desync flings one vessel far beyond it.
+			if worst_spread > 900.0:
+				return _fail_now("vessels fell %.1f apart - the fleet came apart rather than moving together" % worst_spread)
+			print("no vessel outran its own top speed, and none broke formation")
+
+			print("TEST_FLEET_SPEED_BOUNDED: PASS")
+			quit(0)
+			return true
+	return false
+
+
+func _watch_speeds() -> void:
+	var boost: float = game_state.fleet_speed_multiplier
+	for ship in fleet.ships:
+		if not is_instance_valid(ship):
+			continue
+		fastest_seen = maxf(fastest_seen, ship.velocity.length() / (ship.max_speed * boost))
+		for other in fleet.ships:
+			if is_instance_valid(other):
+				worst_spread = maxf(worst_spread, ship.position.distance_to(other.position))
+
+
+# fastest_seen is carried as a RATIO of each vessel's own limit, so a mixed
+# fleet with different top speeds would be judged per vessel rather than
+# against a single global number.
+func _check_speed_bound(context: String) -> bool:
+	if fastest_seen > SPEED_TOLERANCE:
+		_fail_now("a vessel reached %.2fx its own top speed %s - individual speed is not bounded" \
+			% [fastest_seen, context])
+		return false
+	return true
+
+
+func _pivot_formation(angle: float) -> void:
+	var rotated: Array = []
+	for offset in game_state.formation:
+		rotated.append(Vector2(offset).rotated(angle))
+	game_state.formation = rotated
+	fleet.apply_formation()
+
+
+func _fail_now(message: String) -> bool:
+	print("TEST_FLEET_SPEED_BOUNDED: FAIL (%s)" % message)
+	quit(1)
+	return true
diff --git a/tests/test_fleet_speed_bounded.gd.uid b/tests/test_fleet_speed_bounded.gd.uid
new file mode 100644
index 0000000..43f0546
--- /dev/null
+++ b/tests/test_fleet_speed_bounded.gd.uid
@@ -0,0 +1 @@
+uid://bkcs1gl5h616f
diff --git a/tests/test_lunar_field.gd b/tests/test_lunar_field.gd
new file mode 100644
index 0000000..a6c2f03
--- /dev/null
+++ b/tests/test_lunar_field.gd
@@ -0,0 +1,321 @@
+extends SceneTree
+
+# Headless test: run with
+#   godot --headless -s res://tests/test_lunar_field.gd
+# Forgejo #68: the lunar backdrop shader was the most expensive thing in the
+# surface scene, running a 5x5 (25-sample) neighbour scan on every pixel of a
+# fullscreen rect. It is now 3x3 (9 samples).
+#
+# A fragment shader cannot be asserted on directly from GDScript, so this
+# test guards the REASONING that made the reduction safe. The 5x5 width was
+# insurance against craters observed clipping at cell boundaries on-device -
+# i.e. against a crater reaching further than its nominal radius allowed.
+# The fix was to bound that reach at the source (clamp the centre into its
+# own cell, clamp the radius), which makes a 3x3 scan provably sufficient.
+# If someone later loosens either clamp or raises MAX_RADIUS past a cell, the
+# clipping bug comes straight back - and looks like a GPU mystery rather than
+# an edit. This test makes that edit fail loudly instead.
+#
+# Covers:
+#   A. the shader source still carries every premise the bound rests on
+#      (3x3 loop, clamped centre, clamped radius, MAX_RADIUS below a cell)
+#   B. worst case geometry: even a crater pinned at the far corner of a
+#      ring-2 cell at maximum radius cannot reach a threshold that changes a
+#      pixel. Independent of what the hash returns, so it holds on any driver
+#   C. differential check against the real hash: over thousands of sampled
+#      points, a 3x3 scan and a 5x5 scan produce the SAME rendered output
+#   D. the miss sentinel stays inside mediump range when squared, so it
+#      cannot become +Inf (and then NaN) on a mobile GPU
+
+const SHADER_PATH := "res://lunar_surface.gdshader"
+const TILED_SHADER_PATH := "res://lunar_tiled.gdshader"
+const BACKGROUND_SCRIPT_PATH := "res://LunarBackground.gd"
+# Largest normalized distance any shading term below reacts to. Past this,
+# every smoothstep has saturated and the pixel is plain regolith.
+const MAX_SIGNIFICANT_DISTANCE := 1.15
+const MEDIUMP_MAX := 65504.0
+const SAMPLE_COUNT := 4000
+
+var source: String = ""
+var min_radius: float = 0.0
+var max_radius: float = 0.0
+var miss_distance_sq: float = 0.0
+var start_distance_sq: float = 0.0
+var tile_cells: float = 0.0
+
+
+func _initialize() -> void:
+	var file: FileAccess = FileAccess.open(SHADER_PATH, FileAccess.READ)
+	if file == null:
+		_fail("could not read %s" % SHADER_PATH)
+		return
+	source = file.get_as_text()
+	file.close()
+
+	min_radius = _read_const("MIN_RADIUS")
+	max_radius = _read_const("MAX_RADIUS")
+	miss_distance_sq = _read_const("MISS_DISTANCE_SQ")
+	start_distance_sq = _read_const("START_DISTANCE_SQ")
+	if is_nan(min_radius) or is_nan(max_radius) or is_nan(miss_distance_sq) or is_nan(start_distance_sq):
+		_fail("could not parse the shader's radius/sentinel constants")
+		return
+
+	if not _check_premises():
+		return
+	if not _check_tiling_setup():
+		return
+	if not _check_worst_case_geometry():
+		return
+	if not _check_sentinels():
+		return
+	if not _check_scans_agree():
+		return
+	if not _check_field_is_periodic():
+		return
+
+	print("TEST_LUNAR_FIELD: PASS")
+	quit(0)
+
+
+# --- A. the premises are still in the source ---------------------------------
+func _check_premises() -> bool:
+	# The scan itself. Both loops must be the 3x3 form; a stray -2 anywhere in
+	# the bounds means someone widened it back without updating this test.
+	if not ("for (int dx = -1; dx <= 1; dx++)" in source and "for (int dy = -1; dy <= 1; dy++)" in source):
+		return _fail("the neighbour scan is no longer the 3x3 loop this test reasons about")
+	# The centre clamp. Without it a hash outside [0,1] places a crater centre
+	# outside its own cell and the ring-2 bound below stops holding.
+	if not ("clamp(h.xy, 0.0, 1.0)" in source):
+		return _fail("the crater centre is no longer clamped into its own cell")
+	# The radius clamp. Without it mix() extrapolates into an arbitrarily
+	# large radius, which is the specific failure that caused the original
+	# on-device crater clipping.
+	if not ("clamp(mix(MIN_RADIUS, MAX_RADIUS," in source and "), MIN_RADIUS, MAX_RADIUS)" in source):
+		return _fail("the crater radius is no longer clamped to [MIN_RADIUS, MAX_RADIUS]")
+	# MAX_SIGNIFICANT_DISTANCE below is the furthest normalized distance any
+	# shading term still reacts to, and the overlap suppression is the term
+	# that reaches furthest. Pin it here: raising that upper bound past
+	# MAX_SIGNIFICANT_DISTANCE would make ring-2 craters matter again, and
+	# the geometry check would go on passing against a stale number.
+	if not ("smoothstep(0.85, %.2f, second_nearest)" % MAX_SIGNIFICANT_DISTANCE in source):
+		return _fail("the overlap suppression no longer saturates at %.2f, so the significant range this test assumes is stale" \
+			% MAX_SIGNIFICANT_DISTANCE)
+	print("shader still clamps centre and radius, still scans 3x3, still saturates by %.2f" % MAX_SIGNIFICANT_DISTANCE)
+	return true
+
+
+# --- E. the tiling rig is wired to one shared period -------------------------
+# The tile period appears in three places - the field shader that bakes it,
+# the tiled shader that scrolls it, and the GDScript that sizes the bake and
+# wraps the camera. If they ever disagree the seam stops being seamless, and
+# it fails as a faint repeating discontinuity rather than as an error.
+func _check_tiling_setup() -> bool:
+	if not ("mod(cell + offset, tile_cells)" in source):
+		return _fail("the field shader no longer wraps the cell index, so the baked tile would not be seamless")
+
+	var script_file: FileAccess = FileAccess.open(BACKGROUND_SCRIPT_PATH, FileAccess.READ)
+	if script_file == null:
+		return _fail("could not read %s" % BACKGROUND_SCRIPT_PATH)
+	var script_source: String = script_file.get_as_text()
+	script_file.close()
+
+	var regex := RegEx.new()
+	regex.compile("const\\s+TILE_CELLS\\s*:\\s*float\\s*=\\s*([0-9.]+)")
+	var found: RegExMatch = regex.search(script_source)
+	if found == null:
+		return _fail("LunarBackground.gd no longer declares TILE_CELLS, the shared tile period")
+	tile_cells = float(found.get_string(1))
+	if tile_cells < 4.0:
+		return _fail("a tile period of %.0f cells is too short to read as anything but a repeat" % tile_cells)
+
+	# The camera index must be wrapped on the GDScript side, in double
+	# precision, before it reaches the shader - the whole point of the
+	# existing cell/fraction split is that the raw index is too large for a
+	# mobile float, and the tiled shader adds it straight into a UV.
+	if not ("fposmod(cell.x, TILE_CELLS)" in script_source):
+		return _fail("LunarBackground.gd no longer wraps the camera cell into the tile before handing it to the shader")
+
+	var tiled_file: FileAccess = FileAccess.open(TILED_SHADER_PATH, FileAccess.READ)
+	if tiled_file == null:
+		return _fail("could not read %s" % TILED_SHADER_PATH)
+	var tiled_source: String = tiled_file.get_as_text()
+	tiled_file.close()
+
+	# repeat_enable is the mechanism that makes the canvas infinite;
+	# mipmaps are what stop the crater field shimmering when zoomed out.
+	if not ("repeat_enable" in tiled_source):
+		return _fail("the tiled shader no longer samples with repeat_enable, so the canvas stops repeating")
+	if not ("filter_linear_mipmap" in tiled_source):
+		return _fail("the tiled shader no longer uses mipmaps, so zooming out will alias the crater field")
+	print("tile period %.0f cells, wrapped in GDScript, sampled with repeat + mipmaps" % tile_cells)
+	return true
+
+
+# --- F. the field really is seamless -----------------------------------------
+# Periodicity is asserted directly rather than inferred from the wrap being
+# present: the same point one whole tile away must render identically. A seam
+# is exactly the case where it does not.
+func _check_field_is_periodic() -> bool:
+	var rng := RandomNumberGenerator.new()
+	rng.seed = 6800
+	var shifts: Array = [
+		Vector2(tile_cells, 0.0),
+		Vector2(0.0, tile_cells),
+		Vector2(tile_cells, tile_cells),
+		Vector2(-tile_cells * 3.0, tile_cells * 2.0),
+	]
+	for i in range(SAMPLE_COUNT):
+		var cell := Vector2(rng.randi_range(-4000, 4000), rng.randi_range(-4000, 4000))
+		var local := Vector2(rng.randf(), rng.randf())
+		var here := _shade(cell, local, 1)
+		for shift in shifts:
+			var there := _shade(cell + shift, local, 1)
+			for k in range(here.size()):
+				if absf(here[k] - there[k]) > 0.0001:
+					return _fail("the field is not periodic: cell %s and cell %s render differently (term %d)" \
+						% [cell, cell + shift, k])
+	print("%d sampled points: the field repeats exactly every %.0f cells in both axes" % [SAMPLE_COUNT, tile_cells])
+	return true
+
+
+# --- B. worst case geometry, independent of the hash -------------------------
+func _check_worst_case_geometry() -> bool:
+	if max_radius >= 1.0:
+		return _fail("MAX_RADIUS is %.3f - a crater at least a full cell wide can reach past a 3x3 scan" % max_radius)
+	if min_radius <= 0.0 or min_radius > max_radius:
+		return _fail("MIN_RADIUS %.3f is not a sane lower bound below MAX_RADIUS %.3f" % [min_radius, max_radius])
+
+	# Closest approach between the sampled pixel and ANY crater centre two
+	# cells out. The pixel's local coordinate spans [0,1]; a ring-2 cell spans
+	# [2,3] (or [-2,-1]), and the centre clamp keeps the centre inside it. So
+	# the gap is at least one whole cell however the hash lands.
+	var closest_ring_two_distance: float = 1.0
+	var closest_normalized: float = closest_ring_two_distance / max_radius
+	if closest_normalized <= MAX_SIGNIFICANT_DISTANCE:
+		return _fail("a crater two cells out reaches a normalized distance of %.2f, inside the significant range (%.2f) - a 3x3 scan would clip it" \
+			% [closest_normalized, MAX_SIGNIFICANT_DISTANCE])
+	print("worst case ring-2 crater lands at %.2f, clear of the %.2f threshold (%.1fx margin)" \
+		% [closest_normalized, MAX_SIGNIFICANT_DISTANCE, closest_normalized / MAX_SIGNIFICANT_DISTANCE])
+	return true
+
+
+# --- D. the sentinels cannot overflow a mobile float -------------------------
+func _check_sentinels() -> bool:
+	# The largest value the loop can actually carry: a real squared distance
+	# plus the miss sentinel added on top of it.
+	var largest_real_sq: float = pow(sqrt(8.0) / min_radius, 2.0)
+	var largest_carried: float = miss_distance_sq + largest_real_sq
+	if largest_carried >= MEDIUMP_MAX:
+		return _fail("the loop can carry %.0f, past the mediump ceiling %.0f - it becomes +Inf and then NaN on a mobile GPU" \
+			% [largest_carried, MEDIUMP_MAX])
+	if miss_distance_sq <= largest_real_sq:
+		return _fail("MISS_DISTANCE_SQ %.0f does not beat the largest real squared distance %.0f, so an empty cell could win the scan" \
+			% [miss_distance_sq, largest_real_sq])
+	if start_distance_sq <= largest_carried:
+		return _fail("START_DISTANCE_SQ %.0f is not above every value the loop can produce (%.0f), so the winning offset can stay unset" \
+			% [start_distance_sq, largest_carried])
+	print("sentinels ordered correctly and %.0f stays inside the mediump ceiling %.0f" % [largest_carried, MEDIUMP_MAX])
+	return true
+
+
+# --- C. 3x3 and 5x5 render the same thing ------------------------------------
+func _check_scans_agree() -> bool:
+	# The hash is ported from the shader below. It will not be bit-identical
+	# to any given GPU's evaluation, and does not need to be: what is being
+	# checked is that dropping the outer ring changes nothing, which follows
+	# from the clamped bounds rather than from the hash's exact values. The
+	# port's job is to catch a mistake in that reasoning on realistic inputs,
+	# not to emulate a driver.
+	var rng := RandomNumberGenerator.new()
+	rng.seed = 68
+	var worst_delta: float = 0.0
+	for i in range(SAMPLE_COUNT):
+		# Cell indices deliberately reach into the thousands - the same
+		# magnitudes the camera actually produces after flying a while.
+		var cell := Vector2(rng.randi_range(-4000, 4000), rng.randi_range(-4000, 4000))
+		var local := Vector2(rng.randf(), rng.randf())
+		var near := _shade(cell, local, 1)
+		var far := _shade(cell, local, 2)
+		for k in range(near.size()):
+			var delta: float = absf(near[k] - far[k])
+			worst_delta = maxf(worst_delta, delta)
+			if delta > 0.0001:
+				return _fail("3x3 and 5x5 scans disagree at cell %s local %s: term %d differs by %f" \
+					% [cell, local, k, delta])
+	print("%d sampled points: 3x3 and 5x5 scans agree exactly (worst term delta %.8f)" % [SAMPLE_COUNT, worst_delta])
+	return true
+
+
+# The three values the shader's colour is actually a function of. Comparing
+# these rather than raw `nearest` is deliberate: a 3x3 scan can legitimately
+# report a different nearest distance than a 5x5 one (it may find no crater
+# where 5x5 found a far one), and what matters is only that the PIXEL comes
+# out the same colour.
+func _shade(cell: Vector2, local: Vector2, ring: int) -> Array:
+	var nearest_sq: float = start_distance_sq
+	var second_sq: float = start_distance_sq
+	var nearest_offset := Vector2(0.0, 1.0)
+
+	for dx in range(-ring, ring + 1):
+		for dy in range(-ring, ring + 1):
+			var offset := Vector2(dx, dy)
+			var neighbor: Vector2 = cell + offset
+			# Same wrap the shader does, and the reason the field tiles.
+			neighbor = Vector2(fposmod(neighbor.x, tile_cells), fposmod(neighbor.y, tile_cells))
+			var h: Vector4 = _hash42(neighbor)
+			var has_crater: float = 1.0 if h.z >= 0.35 else 0.0
+			var centre: Vector2 = offset + Vector2(clampf(h.x, 0.0, 1.0), clampf(h.y, 0.0, 1.0))
+			var radius: float = clampf(lerpf(min_radius, max_radius, h.w), min_radius, max_radius)
+			var to_sample: Vector2 = local - centre
+			var normalized_sq: float = to_sample.length_squared() / (radius * radius) \
+				+ (1.0 - has_crater) * miss_distance_sq
+			if normalized_sq < nearest_sq:
+				second_sq = nearest_sq
+				nearest_sq = normalized_sq
+				nearest_offset = to_sample
+			elif normalized_sq < second_sq:
+				second_sq = normalized_sq
+
+	var nearest: float = sqrt(nearest_sq)
+	var second: float = sqrt(second_sq)
+	var offset_length: float = nearest_offset.length()
+	var nearest_dir: Vector2 = nearest_offset / offset_length if offset_length > 0.0001 else Vector2(0.0, 1.0)
+	var facing: float = nearest_dir.dot(Vector2(-0.6, -0.8).normalized())
+
+	var floor_amount: float = 1.0 - smoothstep(0.45, 0.9, nearest)
+	var rim_band: float = smoothstep(0.55, 0.85, nearest) * (1.0 - smoothstep(0.85, 1.0, nearest))
+	rim_band *= smoothstep(0.85, 1.15, second)
+	# facing only reaches the output multiplied by rim_band, so folding it in
+	# here keeps an irrelevant direction difference deep inside a crater floor
+	# from reading as a visual difference.
+	return [floor_amount, rim_band * clampf(facing, 0.0, 1.0), rim_band * clampf(-facing, 0.0, 1.0)]
+
+
+func _hash42(p: Vector2) -> Vector4:
+	var p4 := _fract4(Vector4(p.x, p.y, p.x, p.y) * Vector4(0.1031, 0.1030, 0.0973, 0.1099))
+	var d: float = p4.dot(Vector4(p4.w, p4.z, p4.x, p4.y) + Vector4(33.33, 33.33, 33.33, 33.33))
+	p4 += Vector4(d, d, d, d)
+	# fract((p4.xxyz + p4.yzzw) * p4.zywx)
+	var a := Vector4(p4.x, p4.x, p4.y, p4.z)
+	var b := Vector4(p4.y, p4.z, p4.z, p4.w)
+	var c := Vector4(p4.z, p4.y, p4.w, p4.x)
+	return _fract4((a + b) * c)
+
+
+func _fract4(v: Vector4) -> Vector4:
+	return Vector4(v.x - floor(v.x), v.y - floor(v.y), v.z - floor(v.z), v.w - floor(v.w))
+
+
+func _read_const(name: String) -> float:
+	var regex := RegEx.new()
+	regex.compile("const\\s+float\\s+" + name + "\\s*=\\s*([0-9.eE+-]+)")
+	var found: RegExMatch = regex.search(source)
+	if found == null:
+		return NAN
+	return float(found.get_string(1))
+
+
+func _fail(message: String) -> bool:
+	print("TEST_LUNAR_FIELD: FAIL (%s)" % message)
+	quit(1)
+	return false
diff --git a/tests/test_lunar_field.gd.uid b/tests/test_lunar_field.gd.uid
new file mode 100644
index 0000000..2570d17
--- /dev/null
+++ b/tests/test_lunar_field.gd.uid
@@ -0,0 +1 @@
+uid://b0bjyh6fn2v34
diff --git a/tests/test_research_lab_extractor_gate.gd.uid b/tests/test_research_lab_extractor_gate.gd.uid
new file mode 100644
index 0000000..6b5f117
--- /dev/null
+++ b/tests/test_research_lab_extractor_gate.gd.uid
@@ -0,0 +1 @@
+uid://1ynm1v0c1qfk
diff --git a/tests/test_space_time_distorder.gd b/tests/test_space_time_distorder.gd
index 059321c..ca8d4cd 100644
--- a/tests/test_space_time_distorder.gd
+++ b/tests/test_space_time_distorder.gd
@@ -58,6 +58,17 @@ func _process(delta: float) -> bool:
 				return false
 			main.get_node("EnemySpawner").set_process(false)
 			main.get_node("AsteroidField").set_process(false)
+			# Silencing the spawners is not enough: whatever Main.tscn already
+			# placed keeps moving under its own _physics_process, and this test
+			# flies the fleet several thousand units at up to 3x boost. Losing
+			# the distorder ship to a rock mid-run resets the multiplier -
+			# CORRECTLY, that is what _sync_composition_state is for - and the
+			# test then failed three stages later claiming the multiplier had
+			# not survived a scene swap. Same clean-slate idiom as
+			# test_ship_lab.gd.
+			for hazard in get_nodes_in_group("asteroids") + get_nodes_in_group("enemies"):
+				if is_instance_valid(hazard):
+					hazard.queue_free()
 
 			# --- A. absent, then appears -------------------------------------
 			if fader.visible:
@@ -192,6 +203,13 @@ func _process(delta: float) -> bool:
 			# scenario here since this fleet keeps its distorder ship the
 			# whole way across the swap, via GameState.surviving_vessel_types
 			# exactly like every other vessel type).
+			# Check the premise before relying on it. Everything below is about
+			# the multiplier surviving a scene swap, which is only meaningful
+			# while the fleet still crews a distorder vessel - so if the fleet
+			# lost one on the way here, say THAT rather than reporting a reset
+			# multiplier as if the swap were at fault.
+			if not fleet.has_capability("distorder"):
+				return _fail_now("the fleet lost its distorder vessel before the scene swap, so the multiplier reset is expected rather than a bug")
 			game_state.surviving_ship_count = fleet.ships.size()
 			game_state.surviving_vessel_types = fleet.vessel_types()
 			game_state.planet_id = "test_space_time_distorder"
diff --git a/tests/test_surface_profiles.gd b/tests/test_surface_profiles.gd
index a9acc62..e310f54 100644
--- a/tests/test_surface_profiles.gd
+++ b/tests/test_surface_profiles.gd
@@ -19,7 +19,7 @@ extends SceneTree
 # rather than checking on the same one.
 
 var game_state: Node
-var lunar_shader: Shader
+var scene_shader: Shader
 var gas_shader: Shader
 var rocky_shader_after_compose: Shader
 var scene: Node
@@ -29,7 +29,17 @@ var elapsed: float = 0.0
 
 func _initialize() -> void:
 	game_state = root.get_node("GameState")
-	lunar_shader = load("res://lunar_surface.gdshader")
+	# Whatever PlanetSurface.tscn itself ships with, read from the scene
+	# rather than named by path. The property under test is "a null
+	# background_shader leaves the scene's own background alone" - naming a
+	# specific file here instead made this fail the moment the lunar
+	# background changed implementation (#68 swapped the per-pixel
+	# procedural shader for a baked, tiled one), which is a change this test
+	# has no business having an opinion about.
+	var packed: PackedScene = load("res://PlanetSurface.tscn")
+	var probe: Node = packed.instantiate()
+	scene_shader = probe.get_node("BackgroundLayer/LunarBackground").material.shader
+	probe.free()
 
 	# Loaded by path into a local, not referenced by its bare global
 	# class_name - same load-order hazard PlanetSetups.gd and
@@ -47,8 +57,8 @@ func _initialize() -> void:
 		quit(1)
 		return
 	gas_shader = gas_profile.background_shader
-	if gas_shader == lunar_shader:
-		print("TEST_SURFACE_PROFILES: FAIL (gas profile points at the lunar shader, not its own)")
+	if gas_shader == scene_shader:
+		print("TEST_SURFACE_PROFILES: FAIL (gas profile points at the scene's own shader, not its own)")
 		quit(1)
 		return
 
@@ -79,7 +89,7 @@ func _process(delta: float) -> bool:
 			var gas_bg: ShaderMaterial = scene.get_node("BackgroundLayer/LunarBackground").material
 			scene.free()
 
-			if rocky_shader_after_compose != lunar_shader:
+			if rocky_shader_after_compose != scene_shader:
 				print("TEST_SURFACE_PROFILES: FAIL (landing on a rocky planet changed the background shader)")
 				quit(1)
 				return true
@@ -87,8 +97,8 @@ func _process(delta: float) -> bool:
 				print("TEST_SURFACE_PROFILES: FAIL (landing on a gas giant did not swap in gas_surface.gdshader)")
 				quit(1)
 				return true
-			if gas_bg.shader == lunar_shader:
-				print("TEST_SURFACE_PROFILES: FAIL (gas surface still uses the lunar shader)")
+			if gas_bg.shader == scene_shader:
+				print("TEST_SURFACE_PROFILES: FAIL (gas surface still uses the scene's own lunar background)")
 				quit(1)
 				return true