Remove non-redistributable art from the repo; record licence terms

Researched the licence at each of the four itch.io sources. Two of the four forbid redistribution, and publishing a repository containing them is exactly that, so they are out of the tree. 0x72 DungeonTileset II CC0 1.0 commercial ok, no credit required Helton Yan Pixel Combat CC BY 4.0 commercial ok, CREDIT REQUIRED Fire Pixel Bullet 16x16 custom non-commercial, NO REDISTRIBUTION 750+ Effect and FX Pixel custom non-commercial, NO REDISTRIBUTION Both bdragon1727 packs state verbatim: "You cannot do: Resell / redistribute this asset." The FX pack's paid tier is no better for this purpose -- "You can NOT re-distribute the file, no matter how much you modify it" -- so paying does not unlock it and neither does editing the art. bullets.png and impact.png therefore move to assets/local/, gitignored. Art.bullets_texture() / impact_texture() load them at runtime and return null when absent; the bullet renderer falls back to the generated dot it used before, tinted per kind so bullet types stay distinguishable. Nothing there may be preload()ed -- preload resolves at compile time and would fail the build on every machine without the files, which is every clone. Verified both ways rather than assumed: with the files present the game uses them and no fallback triggers; with them moved aside, 156/156 tests pass and the game runs clean on the generated dots. Added CREDITS.md, because Helton Yan's CC BY 4.0 makes attribution a licence obligation rather than a courtesy. A file in the source tree does not discharge it once the game ships -- an in-game credits screen is now a tracked todo, and flagged as a licence requirement rather than polish. NOT addressed here, and it needs a decision: these files remain in git history at 4a41ccb. Removing them from the tip does not remove them from a clone. If this repo is ever made public, history has to be rewritten (git filter-repo) and force-pushed. Also, both bdragon packs are non-commercial in their free tier, which conflicts with the stated Steam goal -- either contribute for the commercial tier (still no redistribution) or replace with CC0 art, which would solve both problems and let the assets back into the repo.
Replace placeholder rendering with real sprites and audio
2026-09-03 23:52:41 +02:00 · 2026-09-03 23:43:13 +02:00
27 changed files with 743 additions and 110 deletions
@@ -1,5 +1,13 @@
 # Godot's import cache and editor state. Regenerated by `godot --import`.
 .godot/
+# Assets whose licence forbids redistribution. bdragon1727's packs say
+# plainly: "You cannot do: Resell / redistribute this asset." Publishing a repo
+# containing them IS redistribution, so they stay local-only. The game loads
+# them if present and falls back to generated placeholders if not, so a clone
+# without them still runs. See docs/ASSETS.md.
+/assets/local/*
+!/assets/local/README.md
+
 # Raw asset packs: gigabytes of source artwork and audio. Redistributable
 # third-party material belongs where it was bought or downloaded, not in a code
 # repo. The directory itself and its guards stay tracked, so a fresh clone has
@@ -0,0 +1,30 @@
+# Credits
+
+Third-party assets used in Transcience, with the attribution their licences
+require.
+
+## Audio
+
+**Pixel Combat SFX** — [Helton Yan](https://heltonyan.itch.io/pixelcombat)
+Licensed under [CC BY 4.0](https://creativecommons.org/licenses/by/4.0/).
+Converted to 16-bit / 44.1 kHz mono and trimmed for use in game.
+
+> Attribution is **required** by this licence, not optional. It has to appear
+> somewhere a player can reach — this file is not enough on its own once the
+> game ships. See docs/ROADMAP.md.
+
+## Art
+
+**16x16 DungeonTileset II** — [0x72 (Robert Norenberg)](https://0x72.itch.io/dungeontileset-ii)
+Released under [CC0 1.0](https://creativecommons.org/publicdomain/zero/1.0/)
+(public domain). Credit is not required; it is here because the work deserves
+it.
+
+## Not distributed with this repository
+
+Two packs are used locally but deliberately **excluded** from the repository,
+because their licences forbid redistribution. They are not part of any build
+made from this source alone. See [docs/ASSETS.md](docs/ASSETS.md).
+
+- Fire Pixel Bullet 16x16 — [bdragon1727](https://bdragon1727.itch.io/fire-pixel-bullet-16x16)
+- 750+ Effect and FX Pixel All — [bdragon1727](https://bdragon1727.itch.io/750-effect-and-fx-pixel-all)
@@ -42,6 +42,7 @@ will otherwise cost an afternoon.

 - [docs/ROADMAP.md](docs/ROADMAP.md) — what is built, what is next, where each feature lives
 - [docs/DECISIONS.md](docs/DECISIONS.md) — settled design decisions and their reasoning
+- [CREDITS.md](CREDITS.md) — third-party asset attribution
 - [CLAUDE.md](CLAUDE.md) — commands, invariants, Godot CLI gotchas
 - [docs/WORKFLOW.md](docs/WORKFLOW.md) — agent-assisted Godot development, and why the setup looks like this
 - [docs/ARCHITECTURE.md](docs/ARCHITECTURE.md) — code map and the node-free simulation
@@ -0,0 +1,24 @@
+[remap]
+
+importer="wav"
+type="AudioStreamWAV"
+uid="uid://ba050ytxjw6uf"
+path="res://.godot/imported/boss_death.wav-0f78bd9c615fc1e1f69662e3e2b02b1e.sample"
+
+[deps]
+
+source_file="res://assets/audio/sfx/boss_death.wav"
+dest_files=["res://.godot/imported/boss_death.wav-0f78bd9c615fc1e1f69662e3e2b02b1e.sample"]
+
+[params]
+
+force/8_bit=false
+force/mono=false
+force/max_rate=false
+force/max_rate_hz=44100
+edit/trim=false
+edit/normalize=false
+edit/loop_mode=0
+edit/loop_begin=0
+edit/loop_end=-1
+compress/mode=2
@@ -0,0 +1,24 @@
+[remap]
+
+importer="wav"
+type="AudioStreamWAV"
+uid="uid://b4yijsry80ccc"
+path="res://.godot/imported/enemy_death.wav-6bae1d1bbf98e070071e748aa5403ba3.sample"
+
+[deps]
+
+source_file="res://assets/audio/sfx/enemy_death.wav"
+dest_files=["res://.godot/imported/enemy_death.wav-6bae1d1bbf98e070071e748aa5403ba3.sample"]
+
+[params]
+
+force/8_bit=false
+force/mono=false
+force/max_rate=false
+force/max_rate_hz=44100
+edit/trim=false
+edit/normalize=false
+edit/loop_mode=0
+edit/loop_begin=0
+edit/loop_end=-1
+compress/mode=2
@@ -0,0 +1,24 @@
+[remap]
+
+importer="wav"
+type="AudioStreamWAV"
+uid="uid://c7abhuhkwrnbi"
+path="res://.godot/imported/player_hit.wav-478748d8be6b3a13fa393c622448db8e.sample"
+
+[deps]
+
+source_file="res://assets/audio/sfx/player_hit.wav"
+dest_files=["res://.godot/imported/player_hit.wav-478748d8be6b3a13fa393c622448db8e.sample"]
+
+[params]
+
+force/8_bit=false
+force/mono=false
+force/max_rate=false
+force/max_rate_hz=44100
+edit/trim=false
+edit/normalize=false
+edit/loop_mode=0
+edit/loop_begin=0
+edit/loop_end=-1
+compress/mode=2
@@ -0,0 +1,24 @@
+[remap]
+
+importer="wav"
+type="AudioStreamWAV"
+uid="uid://cgxntaxdtxyqp"
+path="res://.godot/imported/shoot.wav-f3ce9b4ae60220ecd3cf78df7278a10f.sample"
+
+[deps]
+
+source_file="res://assets/audio/sfx/shoot.wav"
+dest_files=["res://.godot/imported/shoot.wav-f3ce9b4ae60220ecd3cf78df7278a10f.sample"]
+
+[params]
+
+force/8_bit=false
+force/mono=false
+force/max_rate=false
+force/max_rate_hz=44100
+edit/trim=false
+edit/normalize=false
+edit/loop_mode=0
+edit/loop_begin=0
+edit/loop_end=-1
+compress/mode=2
@@ -0,0 +1,24 @@
+# Local-only assets
+
+Files here are **deliberately not in git**, because their licences forbid
+redistribution — and publishing a repository containing them is redistribution.
+
+Currently:
+
+| File | Pack | Restriction |
+| --- | --- | --- |
+| `bullets.png` | [Fire Pixel Bullet 16x16](https://bdragon1727.itch.io/fire-pixel-bullet-16x16) | "You cannot do: Resell / redistribute this asset." Free tier is non-commercial only. |
+| `impact.png` | [750 Effect and FX Pixel All](https://bdragon1727.itch.io/750-effect-and-fx-pixel-all) | Same wording. Even the paid tier: "You can NOT re-distribute the file, no matter how much you modify it." |
+
+The game degrades rather than breaks without them: `Art.bullets_texture()`
+returns null and the renderer falls back to a generated dot. That fallback is
+what a fresh clone gets, and it is why nothing here may be `preload()`ed —
+`preload` is resolved at compile time and would fail the whole build on a
+machine that does not have these files.
+
+To restore them locally, copy from `assetpacks/` (also untracked):
+
+```
+cp "assetpacks/New_All_Fire_Bullet_Pixel_16x16/All_Fire_Bullet_Pixel_16x16_00.png" assets/local/bullets.png
+cp "assetpacks/Effect and FX Pixel All Free/Part 1/03.png" assets/local/impact.png
+```
@@ -0,0 +1,40 @@
+[remap]
+
+importer="texture"
+type="CompressedTexture2D"
+uid="uid://bircs55cjivvx"
+path="res://.godot/imported/dungeon_tileset.png-32ddb268ab9db09e8f122db6a00ca77a.ctex"
+metadata={
+"vram_texture": false
+}
+
+[deps]
+
+source_file="res://assets/sprites/dungeon_tileset.png"
+dest_files=["res://.godot/imported/dungeon_tileset.png-32ddb268ab9db09e8f122db6a00ca77a.ctex"]
+
+[params]
+
+compress/mode=0
+compress/high_quality=false
+compress/lossy_quality=0.7
+compress/uastc_level=0
+compress/rdo_quality_loss=0.0
+compress/hdr_compression=1
+compress/normal_map=0
+compress/channel_pack=0
+mipmaps/generate=false
+mipmaps/limit=-1
+roughness/mode=0
+roughness/src_normal=""
+process/channel_remap/red=0
+process/channel_remap/green=1
+process/channel_remap/blue=2
+process/channel_remap/alpha=3
+process/fix_alpha_border=true
+process/premult_alpha=false
+process/normal_map_invert_y=false
+process/hdr_as_srgb=false
+process/hdr_clamp_exposure=false
+process/size_limit=0
+detect_3d/compress_to=1
@@ -5,35 +5,76 @@ The packs themselves are **not in git** (see
 licence files are not either. This file is the record that survives. Keep it
 current when a pack is added or removed.

-## Why nothing is imported yet
+## How assets get from a pack into the game

-`assetpacks/` carries a `.gdignore`, so Godot skips it entirely. Nothing there
-can be referenced from a scene or script until it is copied into
-`res://assets/` in game-ready form. That is deliberate: the tree is 3.9 GB, and
-`tools/check.sh` runs `--import`, which would otherwise walk all of it on every
-run.
+`assetpacks/` carries a `.gdignore`, so Godot skips it entirely — nothing there
+can be referenced from a scene or script. Files are copied into `res://assets/`
+in game-ready form, and only then imported. The tree is 3.9 GB and
+`tools/check.sh` runs `--import`, which would otherwise walk all of it every run.

-## Packs
+What is in the game today totals **548 KB** across seven files: three sprite
+sheets and four sounds. Sprite rects and sound paths are all declared in one
+place, [src/view/art.gd](../src/view/art.gd), and
+`tests/unit/test_art.gd` asserts every rect lands inside its texture — a wrong
+atlas coordinate does not error, it silently draws the wrong pixels.

-| Pack | Size | Intended use | Licence |
-| --- | --- | --- | --- |
-| 0x72 Dungeon Tileset II v1.7 | 1.6 MB | Dungeon tiles — maps to the `MapGrid.Kind` tiles the generator already emits | **Unrecorded.** Bundled README is technical, not legal. Widely distributed as CC0 by Robert Norenberg (0x72), but confirm at the source before shipping. |
-| Effect and FX Pixel All Free | 29 MB | Hit flashes, muzzle flashes, death effects | **Unrecorded** — no licence file in the pack. |
-| Helton Yan's Pixel Combat | 3.9 GB | Combat SFX | **Unrecorded** — no licence file in the pack. |
-| New All Fire Bullet Pixel 16x16 | 360 KB | Bullet sprites, to replace the generated dot in `bullet_renderer.gd` | **Unrecorded** — no licence file in the pack. |
-| `considering_dont_use_yet/` — RF Catacombs v1.0 | part of 1.6 MB | Undecided | **Public domain**, per bundled `public-license.txt`. "Free to use, personal or commercial. Credit not required but appreciated. You can edit, but not resell the asset pack." Artwork by Szadi art. |
-| `considering_dont_use_yet/` — Tiny RPG Character Pack 02, neo_zero v1.0 / 3.0 demo | part of 1.6 MB | Undecided | **Unrecorded.** |
+## Licence findings

-### Action needed before shipping anything
+Checked against each pack's itch.io page. **Two of the four forbid
+redistribution**, which is what publishing a repository containing them would
+be — so they are not in the repository.

-Four of the six packs arrived with no licence text at all. Redistribution terms
-for pixel-art and audio packs vary a lot — some free packs forbid commercial
-use, some require credit, and "free demo" versions (two of the undecided packs
-are demos) are often more restricted than the paid ones.
+| Pack | Licence | Commercial | Credit | In this repo? |
+| --- | --- | --- | --- | --- |
+| [0x72 DungeonTileset II](https://0x72.itch.io/dungeontileset-ii) | **CC0 1.0** (public domain) | Yes | Not required | **Yes** — `assets/sprites/dungeon_tileset.png` |
+| [Helton Yan Pixel Combat](https://heltonyan.itch.io/pixelcombat) | **CC BY 4.0** | Yes | **Required** | **Yes** — `assets/audio/sfx/` |
+| [Fire Pixel Bullet 16x16](https://bdragon1727.itch.io/fire-pixel-bullet-16x16) | Custom | **Non-commercial only** unless you contribute | Encouraged | **No** — local only |
+| [750+ Effect and FX Pixel All](https://bdragon1727.itch.io/750-effect-and-fx-pixel-all) | Custom | **Non-commercial only** unless you contribute | Encouraged | **No** — local only |

-Record the source URL and terms for each **Unrecorded** row above before any of
-it goes into a build. The `considering_dont_use_yet/` packs are the user's own
-"not chosen yet" marker; leave them there until that changes.
+### The blocking clause
+
+Both bdragon1727 packs state, verbatim:
+
+> **You cannot do:** Resell / redistribute this asset.
+
+And the paid tier of the FX pack is no better for this purpose:
+
+> You can NOT re-distribute the file, no matter how much you modify it you can
+> use it but not share or re-sell it.
+
+Putting those files in a public repository distributes them to everyone who
+clones it, which is squarely what that forbids. Paying for the commercial tier
+does **not** unlock it — the restriction survives payment and survives
+modification.
+
+So they live in `assets/local/`, which is gitignored. `Art.bullets_texture()`
+and `Art.impact_texture()` load them at runtime if present and return null if
+not; the bullet renderer falls back to a generated dot. Verified both ways: with
+the files present the game uses them, and with them hidden the suite still
+passes 156/156 and the game runs.
+
+This is also why nothing there may be `preload()`ed — `preload` resolves at
+compile time and would fail the build on every machine that lacks the files.
+
+### Two obligations this creates
+
+1. **Helton Yan's CC BY 4.0 requires attribution**, and it is not satisfied by
+   a file in the source tree once the game ships. Players need to be able to
+   see it. [CREDITS.md](../CREDITS.md) records it for now; an in-game credits
+   screen is a todo.
+2. **Both bdragon packs are non-commercial in their free tier.** The stated
+   goal is a Steam release. Before that happens they need either a paid
+   contribution to bdragon1727 (which permits commercial use but still not
+   redistribution) or replacement with CC0 art. A CC0 replacement solves both
+   problems at once and lets the assets go back in the repo.
+
+### Not in use
+
+`assetpacks/considering_dont_use_yet/` is the "not chosen" marker and nothing
+there is referenced. It contains RF Catacombs v1.0 (public domain per its
+bundled `public-license.txt` — free for personal or commercial use, credit
+appreciated, no reselling; artwork by Szadi art), plus Tiny RPG Character Pack
+02 and neo_zero demos, whose terms are unrecorded.

 ## Converting audio before use

@@ -53,6 +53,24 @@ draws whatever it holds. The defence is what the server declines to send.

 ---

+## Art and audio · *first pass done*
+
+Placeholders are gone: terrain, actors and bullets are sprites, and four sounds
+play off server events. Enough to prove the pipeline, not a finished look.
+
+| Feature | State | Where |
+| --- | --- | --- |
+| Atlas/sound table in one place | done | [src/view/art.gd](../src/view/art.gd) |
+| Terrain, actors, boss from the 0x72 atlas | done | `WorldView._draw_tile` / `_draw_sprite` |
+| Animated bullet sprites, one MultiMesh per kind | done | [src/view/bullet_renderer.gd](../src/view/bullet_renderer.gd) |
+| SFX pool driven by server events | done | [src/view/sfx.gd](../src/view/sfx.gd) |
+| Rects validated without a display | done | `tests/unit/test_art.gd` |
+| Impact/death VFX animation | todo | `Art.IMPACT` is loaded and validated but nothing plays it yet |
+| Directional sprites, hit flashes, screen shake | todo | |
+| Audio buses and a volume setting | todo | Everything plays on Master at hardcoded dB |
+| **In-game credits screen** | **todo** | Not cosmetic: the SFX are CC BY 4.0 and attribution is a licence *requirement*. [CREDITS.md](../CREDITS.md) is not reachable by a player. |
+| Replace the two non-redistributable packs | todo | Bullet and FX art is local-only and non-commercial. CC0 replacements would let them into the repo and unblock a commercial release. See [ASSETS.md](ASSETS.md). |
+
 ## Stage 2 — Characters, persistence, levels · *todo, next*

 Depends on nothing in Stage 1 except a place to stand. Blocked only on the
@@ -1,10 +1,11 @@
-[gd_scene load_steps=6 format=3]
+[gd_scene load_steps=7 format=3]

 [ext_resource type="Script" path="res://src/view/game_scene.gd" id="1"]
 [ext_resource type="Script" path="res://src/view/world_view.gd" id="2"]
 [ext_resource type="Script" path="res://src/view/bullet_renderer.gd" id="3"]
 [ext_resource type="Script" path="res://src/ui/hud.gd" id="4"]
 [ext_resource type="Script" path="res://src/ui/game_menu.gd" id="5"]
+[ext_resource type="Script" path="res://src/view/sfx.gd" id="6"]

 [node name="Game" type="Node2D"]
 script = ExtResource("1")
@@ -13,7 +14,7 @@ script = ExtResource("1")
 position = Vector2(640, 360)
 script = ExtResource("2")

-[node name="Bullets" type="MultiMeshInstance2D" parent="WorldView"]
+[node name="Bullets" type="Node2D" parent="WorldView"]
 script = ExtResource("3")

 [node name="HUD" type="CanvasLayer" parent="."]
@@ -21,3 +22,6 @@ script = ExtResource("4")

 [node name="GameMenu" type="CanvasLayer" parent="."]
 script = ExtResource("5")
+
+[node name="Sfx" type="Node" parent="."]
+script = ExtResource("6")
@@ -10,6 +10,11 @@ extends Node
 signal instance_changed
 signal hud_dirty
 signal local_hit(damage: int)
+## Cosmetic signals for the view. Every one is raised from a server event, not
+## from a local guess, so what the player hears matches what actually happened.
+signal shot_fired
+signal enemy_died
+signal boss_died

 var my_peer: int = 0
 var instance_id: int = 0
@@ -200,6 +205,12 @@ func _resync_input_tick(server_tick: int, why: String) -> void:
 	GameLog.warn("client", "input re-sync: %s" % why)


+## Whether the local player is moving, for choosing a run vs idle animation.
+## View-only; nothing in the simulation asks.
+func is_moving() -> bool:
+	return not pending.is_empty() and pending[pending.size() - 1].move.length_squared() > 0.04
+
+
 func on_map_chunks(from_instance: int, data: PackedByteArray) -> void:
 	# A chunk still in flight when we changed instances describes the wrong map.
 	if from_instance != instance_id or world.map == null:
@@ -329,6 +340,8 @@ func on_events(data: PackedByteArray) -> void:
 					ev["team"], ev["kind"], ev["accel"], ev["turn"], ev["uid"])
 				if slot >= 0 and catchup > 0:
 					world.pool.advance_slot(slot, catchup)
+				if int(ev["team"]) == SimConfig.TEAM_PLAYER:
+					shot_fired.emit()
 			SimEvent.Type.BULLET_DESPAWN:
 				world.apply_event(ev)
 			SimEvent.Type.PLAYER_HIT:
@@ -346,6 +359,10 @@ func on_events(data: PackedByteArray) -> void:
 					predicted_pos = ev["pos"]
 					pending.clear()
 					hud_dirty.emit()
+			SimEvent.Type.ENEMY_DIED:
+				enemy_died.emit()
+			SimEvent.Type.BOSS_DIED:
+				boss_died.emit()
 			_:
 				pass

@@ -0,0 +1,128 @@
+class_name Art
+extends RefCounted
+## Where every sprite rect and sound file lives.
+##
+## The atlas coordinates below are copied from the pack's own `tile_list_v1.7`,
+## which ships alongside the art. Keeping them in one table rather than scattered
+## through the renderers means re-cutting the atlas is one edit, and a wrong rect
+## is visible here rather than buried in a draw call.
+##
+## Everything in this file is view-only. Nothing under src/sim/ may reference it:
+## the simulation has no idea the game has art.
+
+## Redistributable, so committed and safe to preload.
+const TILESET := preload("res://assets/sprites/dungeon_tileset.png")
+
+## NOT redistributable: bdragon1727's licence says "You cannot do: Resell /
+## redistribute this asset", and shipping them in a public repo would be exactly
+## that. They live in the untracked assets/local/ and are loaded at RUNTIME.
+##
+## preload() would be resolved at compile time and would fail the entire build
+## on any machine that does not have them -- which is every fresh clone. Hence
+## load() behind an existence check, and a generated fallback in the renderer.
+const LOCAL_BULLETS := "res://assets/local/bullets.png"
+const LOCAL_IMPACT := "res://assets/local/impact.png"
+
+static var _bullets: Texture2D = null
+static var _impact: Texture2D = null
+static var _optional_loaded: bool = false
+
+
+static func _load_optional() -> void:
+	if _optional_loaded:
+		return
+	_optional_loaded = true
+	if ResourceLoader.exists(LOCAL_BULLETS):
+		_bullets = load(LOCAL_BULLETS)
+	if ResourceLoader.exists(LOCAL_IMPACT):
+		_impact = load(LOCAL_IMPACT)
+
+
+## Null when the licence-restricted art is not present. Callers must cope.
+static func bullets_texture() -> Texture2D:
+	_load_optional()
+	return _bullets
+
+
+static func impact_texture() -> Texture2D:
+	_load_optional()
+	return _impact
+
+## Source art is 16px; the world's tiles are 32. Drawn at 2x with nearest
+## filtering (project-wide `default_texture_filter=0`) so it stays crisp.
+const SCALE := 2.0
+
+# --- Terrain (0x72 dungeon tileset) -----------------------------------------
+# MapGrid.Kind -> atlas rect. Floors get a few variants picked by position so
+# large rooms are not a single repeated tile.
+const FLOOR_VARIANTS: Array[Rect2] = [
+	Rect2(16, 64, 16, 16), Rect2(32, 64, 16, 16), Rect2(48, 64, 16, 16),
+	Rect2(16, 80, 16, 16), Rect2(32, 80, 16, 16), Rect2(48, 80, 16, 16),
+	Rect2(16, 96, 16, 16), Rect2(32, 96, 16, 16),
+]
+const WALL := Rect2(32, 16, 16, 16)
+const WALL_TOP := Rect2(32, 0, 16, 16)
+const PIT := Rect2(96, 144, 16, 16)          # "hole"
+const BARRICADE := Rect2(16, 32, 16, 16)     # a banner: low, readable, see-over
+
+# --- Actors -----------------------------------------------------------------
+# 4-frame idle loops. Frames are contiguous horizontally, so only the first
+# rect and a count are needed.
+const PLAYER_IDLE := Rect2(128, 100, 16, 28)
+const PLAYER_RUN := Rect2(192, 100, 16, 28)
+const ACTOR_FRAMES := 4
+## Ticks per animation frame.
+const FRAME_TICKS := 8
+
+## EnemyDef.visual -> first idle frame. Order matches Content: drifter, turret,
+## stalker, practice dummy.
+const ENEMY_IDLE: Array[Rect2] = [
+	Rect2(368, 64, 16, 16),    # imp     -> drifter
+	Rect2(368, 88, 16, 16),    # skelet  -> turret
+	Rect2(368, 40, 16, 16),    # goblin  -> stalker
+	Rect2(288, 336, 16, 16),   # red flask -> practice target
+]
+const BOSS_IDLE := Rect2(16, 428, 32, 36)    # big demon
+
+# --- Bullets ----------------------------------------------------------------
+# The pack sheet is a 40x25 grid of 16x16 cells. SimConfig.KIND_* indexes into
+# these, so a new bullet kind is one more entry.
+const BULLET_CELL := 16.0
+const BULLET_CELLS: Array[Vector2i] = [
+	Vector2i(0, 0),    # KIND_PLAYER_SHOT
+	Vector2i(0, 5),    # KIND_ORB
+	Vector2i(0, 10),   # KIND_NEEDLE
+	Vector2i(0, 15),   # KIND_HEAVY
+]
+## Frames in a bullet's animation loop, read left to right from its cell.
+const BULLET_FRAMES := 4
+
+# --- Impact effect ----------------------------------------------------------
+const IMPACT_CELL := 64.0
+const IMPACT_COLUMNS := 13
+const IMPACT_FRAMES := 9
+## Ticks the whole impact animation lasts.
+const IMPACT_TICKS := 27
+
+# --- Sound ------------------------------------------------------------------
+const SFX_SHOOT := preload("res://assets/audio/sfx/shoot.wav")
+const SFX_PLAYER_HIT := preload("res://assets/audio/sfx/player_hit.wav")
+const SFX_ENEMY_DEATH := preload("res://assets/audio/sfx/enemy_death.wav")
+const SFX_BOSS_DEATH := preload("res://assets/audio/sfx/boss_death.wav")
+
+
+## Frame [param n] of a horizontal strip starting at [param first].
+static func frame(first: Rect2, n: int) -> Rect2:
+	return Rect2(first.position + Vector2(first.size.x * float(n), 0.0), first.size)
+
+
+## Which idle/run frame to draw at this tick. Offset by an actor id so a room
+## full of the same enemy does not breathe in unison.
+static func anim_frame(tick: int, offset: int, frames: int = ACTOR_FRAMES) -> int:
+	return posmod((tick / FRAME_TICKS) + offset, frames)
+
+
+## Pick a floor variant from tile position -- stable, so floors do not shimmer
+## as the camera moves.
+static func floor_for(tx: int, ty: int) -> Rect2:
+	return FLOOR_VARIANTS[posmod(tx * 7 + ty * 13, FLOOR_VARIANTS.size())]
@@ -0,0 +1 @@
+uid://clqu3bgl7fd1j
@@ -1,60 +1,114 @@
-extends MultiMeshInstance2D
-## Draws the whole bullet field in one draw call.
+extends Node2D
+## Draws the whole bullet field.
 ##
-## A bullet hell routinely has a thousand bullets on screen. One Node2D each
+## A bullet hell routinely has hundreds of bullets on screen. One Node2D each
 ## would cost more than the simulation does, so the renderer reads the client's
-## [BulletPool] arrays directly and pushes them into a MultiMesh. The sprite is
-## generated at runtime, so the project needs no art to run.
+## [BulletPool] arrays directly and pushes them into MultiMeshes.
+##
+## One MultiMesh per bullet kind rather than one overall: a MultiMeshInstance2D
+## carries a single texture, and each kind needs a different region of the sprite
+## sheet. Four kinds means four draw calls, which is nothing, and it avoids a
+## custom shader passing UV offsets through per-instance custom data.

-const TEXTURE_SIZE := 32
+## Used only in fallback mode, where every bullet is the same generated dot and
+## colour is the only thing distinguishing a kind.
+const _FALLBACK_COLOURS: Array[Color] = [
+	Color(0.45, 0.95, 1.0),   # KIND_PLAYER_SHOT
+	Color(1.0, 0.35, 0.75),   # KIND_ORB
+	Color(1.0, 0.85, 0.3),    # KIND_NEEDLE
+	Color(1.0, 0.45, 0.2),    # KIND_HEAVY
+]

-var _colors := {
-	SimConfig.KIND_PLAYER_SHOT: Color(0.45, 0.95, 1.0),
-	SimConfig.KIND_ORB: Color(1.0, 0.35, 0.75),
-	SimConfig.KIND_NEEDLE: Color(1.0, 0.85, 0.3),
-	SimConfig.KIND_HEAVY: Color(1.0, 0.45, 0.2),
-}
+var _layers: Array[MultiMeshInstance2D] = []
+## Advances the bullets' own animation, independent of the simulation.
+var _anim_tick: int = 0
+## True when the licence-restricted bullet sheet is absent and we are drawing
+## generated dots instead. See Art.bullets_texture().
+var _fallback: bool = false


 func _ready() -> void:
-	texture = _make_dot_texture()
-	var mm := MultiMesh.new()
-	mm.transform_format = MultiMesh.TRANSFORM_2D
-	mm.use_colors = true
+	var sheet := Art.bullets_texture()
+	_fallback = sheet == null
+	var art: Texture2D = sheet if sheet != null else _make_dot_texture()
+	if _fallback:
+		GameLog.info("view", "bullet sheet absent, drawing generated dots")
 	var quad := QuadMesh.new()
 	quad.size = Vector2.ONE
-	mm.mesh = quad
-	mm.instance_count = SimConfig.MAX_BULLETS
-	mm.visible_instance_count = 0
-	multimesh = mm
+	for kind in SimConfig.KIND_HEAVY + 1:
+		var layer := MultiMeshInstance2D.new()
+		layer.texture = art
+		var mm := MultiMesh.new()
+		mm.transform_format = MultiMesh.TRANSFORM_2D
+		mm.use_colors = true
+		mm.mesh = quad
+		mm.instance_count = SimConfig.MAX_BULLETS
+		mm.visible_instance_count = 0
+		layer.multimesh = mm
+		add_child(layer)
+		_layers.append(layer)


-## A soft-edged disc with a bright core, so overlapping bullets stay readable.
+func _process(_delta: float) -> void:
+	_anim_tick += 1
+	if not _fallback:
+		_apply_frame()
+
+
+## A soft-edged disc with a bright core, generated at runtime. This is what the
+## game draws when the bullet sheet is not present, which is the case for any
+## clone of the repository -- the sheet's licence forbids redistributing it.
 func _make_dot_texture() -> ImageTexture:
-	var img := Image.create(TEXTURE_SIZE, TEXTURE_SIZE, false, Image.FORMAT_RGBA8)
-	var centre := Vector2(TEXTURE_SIZE, TEXTURE_SIZE) * 0.5
-	for y in TEXTURE_SIZE:
-		for x in TEXTURE_SIZE:
-			var d := Vector2(x + 0.5, y + 0.5).distance_to(centre) / (TEXTURE_SIZE * 0.5)
-			var alpha := clampf(1.0 - d, 0.0, 1.0)
-			alpha = pow(alpha, 0.6)
+	var size := 32
+	var img := Image.create(size, size, false, Image.FORMAT_RGBA8)
+	var centre := Vector2(size, size) * 0.5
+	for y in size:
+		for x in size:
+			var d := Vector2(x + 0.5, y + 0.5).distance_to(centre) / (size * 0.5)
+			var alpha := pow(clampf(1.0 - d, 0.0, 1.0), 0.6)
 			var core := clampf(1.0 - d * 1.9, 0.0, 1.0)
 			img.set_pixel(x, y, Color(1.0, 1.0, 1.0, alpha).lerp(Color.WHITE, core * 0.8))
 	return ImageTexture.create_from_image(img)


+## Point each layer's texture at this frame's cell in the sheet. Every bullet in
+## a layer shares the frame, which is why this is one region assignment rather
+## than per-instance work.
+func _apply_frame() -> void:
+	var frame := (_anim_tick / 6) % Art.BULLET_FRAMES
+	for kind in _layers.size():
+		var cell: Vector2i = Art.BULLET_CELLS[kind]
+		var region := Rect2(
+			Vector2(float(cell.x + frame), float(cell.y)) * Art.BULLET_CELL,
+			Vector2(Art.BULLET_CELL, Art.BULLET_CELL))
+		var atlas := _layers[kind].texture as AtlasTexture
+		if atlas == null:
+			atlas = AtlasTexture.new()
+			atlas.atlas = Art.bullets_texture()
+			_layers[kind].texture = atlas
+		atlas.region = region
+
+
 func render_pool(pool: BulletPool) -> void:
-	var mm := multimesh
-	var n := 0
+	var counts := PackedInt32Array()
+	counts.resize(_layers.size())
+	counts.fill(0)
 	for i in pool.high_water:
 		if pool.alive[i] == 0:
 			continue
+		var kind := clampi(pool.kind[i], 0, _layers.size() - 1)
+		var n := counts[kind]
 		if n >= SimConfig.MAX_BULLETS:
-			break
-		# The texture's visible disc is about 80% of the quad, so scale up a
-		# little to make the drawn radius match the radius used for hits.
-		var d: float = pool.radius[i] * 2.5
-		mm.set_instance_transform_2d(n, Transform2D(0.0, Vector2(d, d), 0.0, pool.pos[i]))
-		mm.set_instance_color(n, _colors.get(pool.kind[i], Color.WHITE))
-		n += 1
-	mm.visible_instance_count = n
+			continue
+		# The art fills its 16px cell, while the radius is the hitbox. Draw a
+		# little larger so a bullet looks like the threat it is -- the same
+		# "prefer a visible near-miss" trade the ship sprite makes.
+		var d: float = pool.radius[i] * 3.0
+		var angle: float = (pool.vel[i] as Vector2).angle()
+		_layers[kind].multimesh.set_instance_transform_2d(
+			n, Transform2D(angle, Vector2(d, d), 0.0, pool.pos[i]))
+		_layers[kind].multimesh.set_instance_color(n,
+			_FALLBACK_COLOURS[kind] if _fallback else Color.WHITE)
+		counts[kind] = n + 1
+	for kind in _layers.size():
+		_layers[kind].multimesh.visible_instance_count = counts[kind]
@@ -6,6 +6,7 @@ extends Node2D
@onready var world_view: Node2D = $WorldView
@onready var hud: CanvasLayer = $HUD
@onready var menu: CanvasLayer = $GameMenu
+@onready var sfx: Node = $Sfx

 var _bound: ClientRuntime = null

@@ -44,6 +45,9 @@ func _process(_delta: float) -> void:
 		_bound = Net.client
 		if _bound != null and not _bound.local_hit.is_connected(_on_local_hit):
 			_bound.local_hit.connect(_on_local_hit)
+			_bound.shot_fired.connect(func() -> void: sfx.play(Art.SFX_SHOOT, -14.0))
+			_bound.enemy_died.connect(func() -> void: sfx.play(Art.SFX_ENEMY_DEATH, -8.0))
+			_bound.boss_died.connect(func() -> void: sfx.play(Art.SFX_BOSS_DEATH, -2.0))
 	_follow_camera()
 	menu.set_in_dungeon(_bound != null
 		and _bound.instance_kind == Protocol.InstanceKind.DUNGEON)
@@ -69,3 +73,4 @@ func _on_respawn_pressed() -> void:

 func _on_local_hit(_damage: int) -> void:
 	hud.flash_hit()
+	sfx.play(Art.SFX_PLAYER_HIT, -4.0)
@@ -0,0 +1,47 @@
+extends Node
+## Sound effects, played from the events the client already receives.
+##
+## Strictly a view concern: sound is triggered by server events arriving, never
+## by anything the client decides for itself, so what you hear matches what
+## actually happened. Nothing under src/sim/ knows this exists.
+
+## Voices in the pool. Bullet-hell fire rates mean sounds overlap constantly;
+## one player would cut its own tail off on every shot.
+const VOICES := 16
+## Identical sounds landing within this many frames are collapsed into one, so
+## a boss ring hitting eight bullets at once is a bang rather than a wall of
+## clipping.
+const DEDUPE_FRAMES := 2
+
+var _voices: Array[AudioStreamPlayer] = []
+var _next: int = 0
+var _last_played: Dictionary = {}
+var _frame: int = 0
+
+
+func _ready() -> void:
+	for i in VOICES:
+		var p := AudioStreamPlayer.new()
+		p.bus = "Master"
+		add_child(p)
+		_voices.append(p)
+
+
+func _process(_delta: float) -> void:
+	_frame += 1
+
+
+func play(stream: AudioStream, volume_db: float = 0.0) -> void:
+	if stream == null:
+		return
+	var last: int = _last_played.get(stream, -999)
+	if _frame - last < DEDUPE_FRAMES:
+		return
+	_last_played[stream] = _frame
+	# Round-robin rather than "find a free voice": with this many voices the
+	# oldest is always the best one to steal, and it needs no search.
+	var v := _voices[_next]
+	_next = (_next + 1) % _voices.size()
+	v.stream = stream
+	v.volume_db = volume_db
+	v.play()
@@ -0,0 +1 @@
+uid://d0lgvl2fig3i0
@@ -25,12 +25,15 @@ const ENEMY_COLORS := [
 	Color(0.5, 0.55, 0.6),    # dummy
 ]

-@onready var bullets: MultiMeshInstance2D = $Bullets
+@onready var bullets: Node2D = $Bullets

 var client: ClientRuntime = null
+## Drives sprite animation. Local and cosmetic -- never the simulation's tick.
+var _anim_tick: int = 0


 func _process(_delta: float) -> void:
+	_anim_tick += 1
 	client = Net.client
 	if client != null:
 		bullets.render_pool(client.world.pool)
@@ -81,25 +84,26 @@ func _draw_terrain() -> void:
 				continue
 			if not map.has_line_of_sight(eye, centre):
 				continue
-			_draw_tile(kind, centre)
+			_draw_tile(kind, centre, tx, ty)


-func _draw_tile(kind: MapGrid.Kind, centre: Vector2) -> void:
-	var half := MapGrid.TILE * 0.5
-	var r := Rect2(centre - Vector2(half, half), Vector2(MapGrid.TILE, MapGrid.TILE))
+func _draw_tile(kind: MapGrid.Kind, centre: Vector2, tx: int, ty: int) -> void:
+	var dest := Rect2(centre - Vector2(MapGrid.TILE, MapGrid.TILE) * 0.5,
+		Vector2(MapGrid.TILE, MapGrid.TILE))
 	match kind:
 		MapGrid.Kind.FLOOR:
-			draw_rect(r.grow(-1.0), COL_FLOOR)
-		MapGrid.Kind.WALL:
-			draw_rect(r, COL_WALL)
-		MapGrid.Kind.PILLAR:
-			draw_rect(r.grow(-2.0), COL_PILLAR)
+			draw_texture_rect_region(Art.TILESET, dest, Art.floor_for(tx, ty))
+		MapGrid.Kind.WALL, MapGrid.Kind.PILLAR:
+			# Walls that have open floor above them show their capped top, so a
+			# room reads as a room rather than as a field of identical blocks.
+			var open_above := not client.world.map.blocks_sight(tx, ty - 1)
+			draw_texture_rect_region(Art.TILESET, dest,
+				Art.WALL_TOP if open_above else Art.WALL)
 		MapGrid.Kind.PIT:
-			draw_rect(r.grow(-1.0), COL_PIT)
+			draw_texture_rect_region(Art.TILESET, dest, Art.PIT)
 		MapGrid.Kind.BARRICADE:
-			# Drawn short so "you can see over this" reads at a glance.
-			draw_rect(Rect2(r.position + Vector2(0.0, half * 0.5),
-				Vector2(MapGrid.TILE, half)), COL_BARRICADE)
+			draw_texture_rect_region(Art.TILESET, dest, Art.floor_for(tx, ty))
+			draw_texture_rect_region(Art.TILESET, dest, Art.BARRICADE)


 ## Actors are only drawn where the player can actually see them. The server
@@ -123,36 +127,25 @@ func _draw_portal() -> void:


 func _draw_enemy(e: Dictionary) -> void:
-	var col: Color = ENEMY_COLORS[clampi(int(e["visual"]), 0, ENEMY_COLORS.size() - 1)]
+	var visual := clampi(int(e["visual"]), 0, Art.ENEMY_IDLE.size() - 1)
+	var first: Rect2 = Art.ENEMY_IDLE[visual]
+	var src := Art.frame(first, Art.anim_frame(_anim_tick, int(e["id"])))
+	_draw_sprite(Art.TILESET, src, e["pos"])
+	# Health ring stays: the sprite says what it is, the ring says how hurt.
 	var r: float = e["radius"]
-	if int(e["visual"]) == VISUAL_DUMMY:
-		_draw_target_dummy(e["pos"], r, col)
-		return
-	draw_circle(e["pos"], r, Color(col, 0.35))
-	draw_arc(e["pos"], r, 0.0, TAU, 24, col, 2.0)
-
-
-## The hub dummy is a shooting-range target, not an enemy. It used to be drawn
-## as a plain grey disc with 100k hit points, which read as scenery -- nothing
-## about it said "shoot me" and nothing visibly happened when you did. Concentric
-## rings make the intent obvious at a glance.
-func _draw_target_dummy(pos: Vector2, r: float, col: Color) -> void:
-	draw_circle(pos, r, Color(col, 0.18))
-	for i in 3:
-		var ring := r * (1.0 - 0.3 * float(i))
-		draw_arc(pos, ring, 0.0, TAU, 24, Color(col, 0.5 + 0.15 * float(i)), 1.5)
-	draw_circle(pos, r * 0.12, Color(1.0, 0.5, 0.4, 0.9))
+	draw_arc(e["pos"], r + 3.0, 0.0, TAU, 20,
+		Color(0.95, 0.55, 0.55, 0.35), 1.5)


 func _draw_boss() -> void:
 	var b := client.boss_state()
 	if b.is_empty() or not _visible(b["pos"]):
 		return
-	var r: float = client.boss_def.radius if client.boss_def != null else 42.0
 	var pos: Vector2 = b["pos"]
-	draw_circle(pos, r, Color(0.9, 0.3, 0.4, 0.25))
-	draw_arc(pos, r, 0.0, TAU, 48, Color(1.0, 0.4, 0.5), 3.0)
-	draw_arc(pos, r + 10.0, 0.0, TAU, 48, Color(1.0, 0.4, 0.5, 0.25), 1.0)
+	var src := Art.frame(Art.BOSS_IDLE, Art.anim_frame(_anim_tick, 0))
+	_draw_sprite(Art.TILESET, src, pos)
+	var r: float = client.boss_def.radius if client.boss_def != null else 42.0
+	draw_arc(pos, r, 0.0, TAU, 48, Color(1.0, 0.4, 0.5, 0.5), 2.0)


 func _draw_remote_player(p: Dictionary) -> void:
@@ -170,7 +163,7 @@ func _draw_local_player() -> void:
 	if not client.my_alive:
 		_draw_ship(client.predicted_pos, client.aim, COL_DEAD, false)
 		return
-	_draw_ship(client.predicted_pos, client.aim, COL_LOCAL, true)
+	_draw_ship(client.predicted_pos, client.aim, COL_LOCAL, true, client.is_moving())
 	if client.my_spawn_grace:
 		_draw_grace_ring(client.predicted_pos)
 	if client.my_escaping:
@@ -185,18 +178,33 @@ func _draw_grace_ring(pos: Vector2) -> void:
 		Color(0.55, 0.85, 1.0, 0.35 + 0.45 * pulse), 2.0)


-## Drawn at PLAYER_VISUAL_RADIUS, larger than the PLAYER_RADIUS hitbox actually
-## used for hits -- see the comment on those constants in sim_config.gd. The
-## mismatch is deliberate, not a placeholder: a bullet can visibly clip the
-## sprite without registering a hit, which reads as more forgiving of latency
-## than the reverse.
-func _draw_ship(pos: Vector2, aim: float, col: Color, alive: bool) -> void:
-	var r := SimConfig.PLAYER_VISUAL_RADIUS
-	draw_circle(pos, r, Color(col, 0.4 if alive else 0.2))
-	draw_arc(pos, r, 0.0, TAU, 20, col, 2.0)
+## The ship is a sprite now, but the note about sizes still holds: what is drawn
+## is deliberately larger than PLAYER_RADIUS, the hitbox used for hits. A bullet
+## can visibly clip the sprite without landing, which reads as more forgiving of
+## latency than the reverse. See sim_config.gd.
+func _draw_ship(pos: Vector2, aim: float, col: Color, alive: bool, moving: bool = false) -> void:
+	var strip := Art.PLAYER_RUN if moving else Art.PLAYER_IDLE
+	var src := Art.frame(strip, Art.anim_frame(_anim_tick, 0))
+	# Faces the way you aim, which is the whole point of a twin-stick.
+	var flip := absf(wrapf(aim, -PI, PI)) > PI * 0.5
+	_draw_sprite(Art.TILESET, src, pos, col if not alive else Color.WHITE, flip)
 	if alive:
 		var dir := Vector2.RIGHT.rotated(aim)
-		draw_line(pos + dir * r, pos + dir * (r + 12.0), col, 2.0)
+		var r := SimConfig.PLAYER_VISUAL_RADIUS
+		draw_line(pos + dir * r, pos + dir * (r + 10.0), Color(col, 0.8), 2.0)
+
+
+## Draw an atlas region centred on a world position, scaled to match the art's
+## intended pixel size.
+func _draw_sprite(tex: Texture2D, src: Rect2, at: Vector2,
+		modulate: Color = Color.WHITE, flip_h: bool = false) -> void:
+	var size := src.size * Art.SCALE
+	var dest := Rect2(at - size * 0.5, size)
+	if flip_h:
+		# Negative width mirrors the region in place.
+		dest = Rect2(Vector2(dest.position.x + size.x, dest.position.y),
+			Vector2(-size.x, size.y))
+	draw_texture_rect_region(tex, dest, src, modulate)


 ## The escape channel is drawn on the player, not just in the HUD, so other
@@ -0,0 +1,109 @@
+extends GutTest
+## Every sprite rect must land inside its texture.
+##
+## A wrong atlas coordinate does not error — it silently draws whatever happens
+## to be at those pixels, or nothing. Without a display to check against, this
+## is what catches a mistyped rect.
+
+
+func _fits(tex: Texture2D, r: Rect2) -> bool:
+	var size := Vector2(tex.get_size())
+	return r.position.x >= 0.0 and r.position.y >= 0.0 \
+		and r.end.x <= size.x and r.end.y <= size.y
+
+
+func test_the_committed_texture_loads() -> void:
+	assert_not_null(Art.TILESET)
+	assert_gt(Art.TILESET.get_width(), 0)
+
+
+## The licence-restricted sheets are absent from a clean clone by design, so
+## their absence must be a supported state rather than a failure. When they are
+## present locally, the rect tests below still validate them.
+func test_the_game_runs_without_the_restricted_art() -> void:
+	var bullets := Art.bullets_texture()
+	if bullets == null:
+		assert_true(true, "no bullet sheet: renderer falls back to generated dots")
+	else:
+		assert_gt(bullets.get_width(), 0)
+
+
+func test_terrain_rects_are_inside_the_tileset() -> void:
+	var rects: Array[Rect2] = [Art.WALL, Art.WALL_TOP, Art.PIT, Art.BARRICADE]
+	rects.append_array(Art.FLOOR_VARIANTS)
+	for r in rects:
+		assert_true(_fits(Art.TILESET, r), "terrain rect %s is outside the atlas" % r)
+
+
+## Actor strips are read frame by frame along the sheet, so the LAST frame is
+## what has to fit, not the first.
+func test_every_animation_frame_is_inside_the_tileset() -> void:
+	var strips: Array[Rect2] = [Art.PLAYER_IDLE, Art.PLAYER_RUN, Art.BOSS_IDLE]
+	strips.append_array(Art.ENEMY_IDLE)
+	for strip in strips:
+		for n in Art.ACTOR_FRAMES:
+			var f := Art.frame(strip, n)
+			assert_true(_fits(Art.TILESET, f),
+				"frame %d of strip %s runs off the atlas at %s" % [n, strip, f])
+
+
+func test_every_bullet_frame_is_inside_the_sheet() -> void:
+	var sheet := Art.bullets_texture()
+	if sheet == null:
+		pass_test("bullet sheet not present locally; nothing to validate")
+		return
+	for kind in Art.BULLET_CELLS.size():
+		var cell: Vector2i = Art.BULLET_CELLS[kind]
+		for n in Art.BULLET_FRAMES:
+			var r := Rect2(
+				Vector2(float(cell.x + n), float(cell.y)) * Art.BULLET_CELL,
+				Vector2(Art.BULLET_CELL, Art.BULLET_CELL))
+			assert_true(_fits(sheet, r),
+				"bullet kind %d frame %d is outside the sheet at %s" % [kind, n, r])
+
+
+## One entry per SimConfig.KIND_*, or a bullet kind silently renders as another.
+func test_there_is_a_sprite_for_every_bullet_kind() -> void:
+	assert_eq(Art.BULLET_CELLS.size(), SimConfig.KIND_HEAVY + 1)
+
+
+## One entry per EnemyDef.visual actually used by content, or an enemy draws as
+## the wrong creature.
+func test_there_is_a_sprite_for_every_enemy_visual() -> void:
+	for id in [Content.ENEMY_DRIFTER, Content.ENEMY_TURRET,
+			Content.ENEMY_STALKER, Content.ENEMY_DUMMY]:
+		var v := Content.enemy(id).visual
+		assert_lt(v, Art.ENEMY_IDLE.size(), "%s has visual %d with no sprite" % [id, v])
+
+
+func test_impact_sheet_covers_its_declared_frames() -> void:
+	var impact := Art.impact_texture()
+	if impact == null:
+		pass_test("impact sheet not present locally; nothing to validate")
+		return
+	var last := Rect2(
+		Vector2(float((Art.IMPACT_FRAMES - 1) % Art.IMPACT_COLUMNS), 0.0) * Art.IMPACT_CELL,
+		Vector2(Art.IMPACT_CELL, Art.IMPACT_CELL))
+	assert_true(_fits(impact, last))
+
+
+func test_every_sound_loaded_and_is_short_enough_to_be_a_sound_effect() -> void:
+	var sounds := {
+		"shoot": Art.SFX_SHOOT,
+		"player_hit": Art.SFX_PLAYER_HIT,
+		"enemy_death": Art.SFX_ENEMY_DEATH,
+		"boss_death": Art.SFX_BOSS_DEATH,
+	}
+	for name in sounds:
+		var s: AudioStream = sounds[name]
+		assert_not_null(s, "%s failed to load" % name)
+		assert_gt(s.get_length(), 0.0, "%s is empty" % name)
+		# The source pack ships 2.5s+ masters. Anything that long here means the
+		# conversion step was skipped and shots will smear into each other.
+		assert_lt(s.get_length(), 1.5, "%s is too long for a game SFX" % name)
+
+
+func test_the_shoot_sound_is_shorter_than_the_fire_cooldown_allows_to_overlap() -> void:
+	var cooldown := float(SimConfig.PLAYER_FIRE_COOLDOWN) * SimConfig.TICK_DELTA
+	assert_lt(Art.SFX_SHOOT.get_length(), cooldown * 4.0,
+		"held fire would stack more than a few voices of this sound at once")
@@ -0,0 +1 @@
+uid://dl60m1dxxjhew