Pixel Action Adventure

Reference implementation: examples/ember-isle (Phaser 3 + Vite, ~1.5k lines across main.js / sprites.js / biomes.js, no image files). Built from SLYNYRD's Pixelblog 36 — 8-bit Adventure and iterated against a reference screenshot, so the art rules below are the ones that closed the gap between "procedural placeholder" and "reads as real pixel art".

Genre tag

Set gdd.genre to "pixel-action-adventure". Win = beat the last level's boss; lose = hearts reach 0 (retry current level with progress kept). QA must drive a full campaign run (see QA), not just level 1.

Art: procedural pixel art that doesn't look procedural

• One tiny rasterizer, not a drawing library. A Pix class (w, h, color-per-pixel array) with fill((x,y) => color|null), set, outline(color) and fromGrid(rows, palette). makeTex(scene, key, frames) blits frames side by side into one canvas texture and registers frame indices. Every sprite, icon, prop and effect goes through these two functions.
• Auto-outline is the single biggest quality lever. Fill shapes with 2–3 flat shades (light top-left, base, dark bottom rim), then outline() adds a 1px dark outline around every non-empty pixel (4-neighbour). Use a tinted dark per subject (indigo #1d1b3a for characters, deep green for foliage, near-black red for volcanic props) — never pure black.
• Characters: hand-authored grids (16×16, 3 colors + outline, '.' = transparent). Validate every row's width at load (fromGrid throws) — an off-by-one row silently shears the sprite otherwise. Share rows between frames by array spread ([...head, ...face, ...legsA]) instead of duplicating whole frames.
• Props/effects: shape math. Palm = segmented curved trunk + 7 leaf quads split light/dark along the midrib (sign of a cross product). Bush/canopy = disc with a repeating 4×3 "scallop" mask. Pine = 3 stacked triangles with a 2px snow band along each slanted edge. Volcano = shaded cone (rel = dx/halfWidth → light/mid/dark thirds) + strata lines + sinuous lava streams + elliptical glowing crater.
• Recolor, don't redraw, for variety. recolor(pix, {srcHex: dstHex}) over a per-biome map turns green slimes into purple poison / ice / magma slimes. Keep source palettes disjoint across enemy kinds so one map serves all.
• Pixel font for anything big. Phaser Text at 8px blurs under FIT scaling. A 5×7 bitmap font (35-char bitstrings per glyph) rendered through Pix at integer scale, with a vertical color gradient, outline, and a darker 3px "extrude" underneath gives crisp logos ("GAME OVER", title) and menus. Cache textures by style + string; count-up stats just swap cached textures.

Terrain: noise + distance fields, not autotiles

Paint the whole map once per level into one ImageData (e.g. 1024×640 px) instead of tiling it — this is what makes coastlines and grass patches organic instead of square.

1. Type per pixel from smooth value-noise fbm: liquid ('coast' = diagonal sea with noisy edge, 'river' = sinuous band with 2-tile bridge columns, 'lakes' = fbm threshold blobs kept away from spawn), secondary ground (grass/ice/ash) by a second fbm threshold with a margin from liquid, else base ground. Raised plateaus/mesas are tile-grid rects ([x0,x1,height] along the top edge, [x0,x1,y0,y1] freestanding); the 2 tiles under an elevated tile become a cliff FACE.
2. Distance fields by multi-source BFS (4-neighbour, capped at 8, typed arrays, runs in ms): distance-to-land inside liquid, distance-to-liquid on land, distance-to-edge inside grass and plateau tops.
3. Bands from distances: liquid ≤2px from land → foam; land ≤1 → dark rim, ≤4 → wet tan, ≤5 → soft; grass edge ≤1 → light rim and a dashed contour at distance 4 ((x+y)%5<3) — that dashed inner line is the signature look of the reference art; plateau top ≤1 → rim, ≤3 → lip highlight. Cliff faces: horizontal strata w = fy + round(2*sin(x*π/8)), 7px bands cycling 3 shades, a lip line every band, dark columns at run ends, near-black base line.
4. Stamps last: pebble clusters on ground, tufts (or glowing cracks) on secondary ground, only where the target pixel type matches.
5. Liquid is a separate scrolling tileSprite (16×16 pattern of scale-shaped "cups") under the ground image, which is transparent wherever liquid is. Lava = same pattern in orange/yellow with sparkle dots, scrolled slower.
6. Collision = tile type at each tile's center → a hidden tilemap layer (setVisible(false), setCollision(1)). Props get small static bodies at their base only (trunk footprint), so the canopy overlaps the player naturally with y-sorted depth.

A biome is only data: a color table for these bands (+ plateau top/face shades), a liquid [base, wave, sparkle], an enemy skin map, a weather kind, and flags (slippery, lavaBombs, redGlow). A new level = one LEVELS entry (biome, seed, liquid mode, thresholds, plateaus, props, foes, quota, hidden weapon).

Combat feel (the article's timings are load-bearing)

• Sword: 3 frames — strike / follow-through / overshoot — at 80 ms each, then 320 ms before the next attack. Draw the swing as a white crescent annulus sector per frame (thickness sin of angle across the arc), pivoted at the hero so 90° rotations cover all four directions.
• Idle and walk share the same 2 frames, only the frame rate differs (2 fps vs ~6.7 fps).
• Hit: enemy flashes red tint-fill then white tint-fill (80 ms each), a flashing X burst (show / blank / inverted), 45 ms physics hit-stop + small camera shake, knockback; kill → 3-frame vaporize (disc → ring → specks) + loot.
• Weapons as one dispatch + one shared resolver: attack() switches on the equipped weapon; every melee/projectile hit goes through strike(dir, hitSet, inRange(x,y,pad), opts) which damages enemies once per attack, bats projectiles back, and cuts bushes. Ember Isle's roster: sword, spear (line hit ≤42px, perp ≤9px), boomerang (out 110px or until a wall, homes back, stuns, drags pickups home), bombs (1.1 s fuse, 2-frame big blast, hurts the player too), fire wand (projectile + 3 burn ticks). Each level hides the next weapon at a reachable tile; the HUD shows owned weapons in numbered slots (1–5, Q/E cycles).
• Dash with i-frames and fading tinted afterimages every 30 ms.

Level loop

• Quota < population: each level shows FOES k/goal; spawn more foes than the goal, and every 2.5 s while under quota spawn one reinforcement ≥10 tiles away and outside the camera rect. Leftover foes stay after the goal (coin farming).
• Reachability first: BFS the tile grid from spawn (walls = solid tiles + non-cuttable prop footprints) and place foes, the weapon pickup and reinforcements only on reachable tiles. With lakes/rivers/plateaus, unreachable spawns otherwise make quotas unwinnable.
• Clear → heart container + portal on the nearest open tile near the player; portal overlap fades out and restarts the scene with {level, hearts, maxHearts, coins, unlocked, weapon, runKills}.
• Boss = scaled (×3) recolored base enemy + crown sprite + HP bar; sheds minions when hit, speeds up below half HP, ends in a chained 2-frame explosion.
• Hazards per biome: slippery ice (velocity lerps toward input at 0.05 instead of snapping), volcano lava bombs (blinking red target ellipse, rock arcs in from the crater, blast hurts player and enemies). Put a set-piece like the volcano on a freestanding stepped mesa mid-map — against the top edge the camera clamp means players only ever see its base.
• Weather is screen-space rectangles (snow falls, embers rise, fireflies blink) wrapped at the viewport edges; crater adds a pulsing red overlay.

Screens

Scenes: Title → Game → End. Title: pixel-font logo with a periodic glint, the camera slowly drifting over level 1's painted map, the cast bobbing, a heart-cursor menu (New Game / Continue from a localStorage save written at each level start, wrapped in try/catch / How to Play). Death: stop music, flash + spin-shrink the hero into a vaporize puff, cam.zoomTo(1.8) + pan, cam.postFX.addColorMatrix().grayscale(), then scene.launch('End') + scene.pause(). End: bouncing title, stats that count up one row at a time, a random tip, Retry / Title (victory variant in gold).

Bugs this genre reliably produces (check each one)

1. Phaser.Input.Keyboard.JustDown drops taps whose keydown and keyup land in the same frame (onUp clears _justDown). Queue actions from keydown-SPACE events instead and consume the flag in update.
2. Scene restart reuses the scene instance: any this.* state (portal, boss, over/leaving flags, HUD refs) leaks into the next level's first updateHud(). Reset per-level state at the top of create(), and clear camera zoom/postFX there too.
3. Physics sprites ignore setPosition for teleports (body overwrites the transform next step); use body.reset(x, y).
4. Set-piece off-camera: anything drawn above y ≈ viewportHeight/2 from the world's top edge is never fully visible during play because the camera is bounded. Check set pieces from a walkable camera position, not with a free camera.

QA

Headless Playwright against window.__gameState (phase, level, kills, goal, weapon, unlocked, enemiesAlive, hearts, coins) and __titleReady / __gameReady / __endReady:

• Title → New Game → play; every level: walk to the weapon pickup, verify it auto-equips, then meet the quota using that weapon (teleport foes next to the player via body.reset, grant i-frames), take the portal; boss → victory screen.
• Assert enemiesAlive > goal at every level start, and that reinforcements appear off-screen after culling foes.
• Death → End screen → Retry lands on the same level with full hearts; Title shows Continue.
• Leave ≥150 ms between synthetic key presses in menu tests — two presses in one frame is a test artifact, not a game bug.
• Screenshot each biome and the set-pieces; compare against the reference image the user gave, not against "looks fine".