16-bit Pixel RPG — our demo

One example among many. Don't reuse its story, arc, shots, props or timings.

Demo: The Last Save Point (54.5 s) · pixel-rpg.mp4 · source in demo/

A 30–60 second film: a lone hero at a save crystal remembers his lost companion through three eras of colour depth, then opens the great door.

Story & structure

A world drawn at 320×180 native pixels, scaled ×6 with nearest-neighbour to 1080p. Every color comes from a limited, indexed palette. Gradients are ordered dither, not blends. Characters are sprites around 22×34 px that animate in a handful of frames. Story is told the way a game tells it: through dialog boxes with portraits, menus, status bars, battle messages and save files.

It is not 2.5D Pixel Art (no depth of field, no bloom, no real-time light), not CRT nostalgia (no scanlines, no grain), and not a parody. It takes the game's systems seriously as a language for feeling.

Never use existing game names, characters, UI frames, fonts, logos, melodies or sound effects. Learn the grammar, not the assets.

Pick stories where the game's own systems carry the emotion. The demo used these native powers, the strongest (the palette collapse and flood) at the emotional peak.

Adapting any topic: find the game system hidden in it. A product launch is a new item obtained (fanfare, item box, stat comparison). A farewell is a save file that is never overwritten. A career is a level-up screen. A city is an overworld map with save points.

Arc for 45–60 s: loneliness (quiet, faded, long scroll) → warmth (a memory) → loss (the system breaks) → resolve (the system restored in full color) → an end card that is also a game prompt (CONTINUE ▶).

Shots

• Output 24 fps. Sprites step at 8 fps (walk) to 12 fps (flames, KO blink). Camera and parallax move on ones at integer pixels. Walk speed 30 px/s ≈ 1.25 px per frame.
• Game-native acting: hop forward to act, cast pose with raised staff, knockback recoil, kneel, then the KO blink (12 fps on/off) and vanish. Breath = shoulders up 1 px for 0.6 s.
• UI motion: windows slide in over 0.3 s (ease-out, integer px). The hand cursor bobs 1 px at 4 fps and stops bobbing when the character hesitates. Text types at 38–40 chars/s (30 for 8-bit), with ▼ blinking at 3 Hz when done.
• Transitions: thumbnail expand + mosaic (block 10 → 1 over 0.75 s); mosaic cross (1 → 16 → 1 over 0.8 s, palette switched at the peak); encounter swirl (polar twist growing with s^1.6, mosaic, Bayer-dissolve to white, 0.8 s); screen shake of 3–2–1 px over 8 frames; palette step fades (4 levels), never alpha.

Score structure

• Music: original chiptune (square 12.5/25/50%, 4-bit triangle, LFSR noise, wavetable). One motif runs through every section as regional variations. The music's fidelity follows the color depth:
• 4-color: mono, 4-bit volume steps, 11 kHz sample-and-hold;
• 8-bit: NES-like, mono;
• 16-bit: stereo with SNES-style echo (3 taps ~180/270/370 ms, feedback 0.35–0.45, low-pass ~3 kHz in the loop);
• present: the same music muffled (LP 2.2 kHz). During the palette collapse, the music loses one layer per step: harmony, then echo and stereo, then bass, then only a single square tone, then one beat of silence exactly when the image reaches the present's grey. The boss prelude is the motif in minor; the full band enters on the bar where color floods back. The end card resolves the phrase the opening left on the dominant.
• Foley, all synthesized and bit-crushed to the scene's era: cursor/select blips, text blips (the companion's are higher and 5-bit), stone footsteps with echo, fire crackle, ward shimmer (triangle arpeggio), charge (rising square + noise), blast (swept low-pass noise + 48 Hz thump, crushed to 6-bit), HP tick-down, KO blink, bit-drop per palette step (lower and coarser each time), save ticks, door grind (brown noise + AM creak), torch ignite, reverse swell.
• One organic sound: the hero's breath before the door, band-passed noise and not crushed. It makes him human at the last moment.
• Silence: after the blast (true zero, echo tails cut too) and the beat before the present.
• Voice: Kokoro bm_george at speed 0.9, first person, 5 short lines. Duck the music ~−7.5 dB under the voice (60 ms attack, 350 ms release). Mix to −14 LUFS, grain 0.

Palette & props

• Resolution & scaling: native 320×180 indexed framebuffer (Uint8Array of palette indices). Present through a lookup table (index → RGB) and scale ×6 nearest-neighbour. Everything, including text, is drawn in the framebuffer. Camera moves are integer pixels; each parallax layer rounds its own offset.
• Master palette: ENDESGA-32 (#be4a2f #d77643 #ead4aa #e4a672 #b86f50 #733e39 #3e2731 #a22633 #e43b44 #f77622 #feae34 #fee761 #63c74d #3e8948 #265c42 #193c3e #124e89 #0099db #2ce8f5 #ffffff #c0cbdc #8b9bb4 #5a6988 #3a4466 #262b44 #181425 #ff0044 #68386c #b55088 #f6757a #e8b796 #c28569), plus protected duplicates (scarf red #e43b44/#a22633/#f6757a, crystal cyan #2ce8f5/#0099db/#ffffff/#124e89) that no palette effect touches.
• Color-depth tables (all computed from the master palette):
• 16-bit: identity.
• 8-bit: nearest of 15 colors #000000 #fcfcfc #a4a4b8 #58587c #1c2c8c #3c7cfc #94e0fc #b8141c #fc7454 #fcb81c #8c4c1c #2c9c2c #fcd8a8 #0c4c18 #4c2410. It needs a dark green and a dark brown, or night grass turns blue.
• 4-color: fixed luminance thresholds (<60, <115, <175) → #1f2a1c #4b5e3a #93a263 #d6dba6. Draw 4-color scenes with the four representative indices (ink / slate / steel / white) so every pixel lands on the intended shade. Render them at 160×90 and double.
• Faded: lum^0.8 × 7 → 7 blue-greys #0e0d17 … #c3c9d6. Do not map by rank: rank mapping crushes the scene to black.
• Collapse steps: 16-color and 8-color subsets that keep warm hues (orange, pink, plum), or the first step turns the frame red. Then 4 grey-blues, 2 tones, faded.
• Light is index stepping: a LIGHT[] / DARK[] table moves each index one step along its ramp. Torch glow, moonlight and fire are Bayer-thresholded rings of LIGHT[LIGHT[c]] / LIGHT[c]. Firelight in an 8-bit scene uses a warm remap (greens → browns → rust), not generic brightening, which turns grass radioactive.
• Dither: 4×4 Bayer for gradients and glows. Light shafts use a flat 50% checker with a 25% edge, which reads cleaner than a gradient.
• Parallax (side-scroller): far wall with arched windows 0.35×, colonnade with banners and torches 0.7×, floor with pseudo-perspective joints 1×, black foreground pillars 1.6×.
• Sprites: a rig (capsule limbs with 3-tone shading from an upper-left light, per-part inner line in the material's darkest tone, global 1-px ink outline) plus hand-placed ASCII heads. One rig gives every pose: walk ×4, attack, hurt, look up, push, sit, kneel, back-view push. For 8-bit scenes use the same rig with the highlight tone removed. Give the hero a silhouette mark: a long scarf whose tails flutter in a 3-frame stepped cycle, plus a cowlick.
• Portraits 32×32, 3/4 view, base face + eye/brow and mouth overlays (neutral, wistful, smile, sad, resolve). They carry all facial acting; the 34-px sprite face has one eye pixel.
• Props: the save crystal is a flat-shaded octahedron rotated in 3D and quantized to 4 protected cyans (8 frames per 90°), with a dithered halo. The great door is a front-on paneled stone door with a sunburst tympanum, voussoirs, a rune ring that splits when it opens, and a rose window above for the tilt-up.

Titles, subtitles & end card

• The dialog box is the subtitle, drawn in the framebuffer at y 134–176:
• three-layer rounded border (ink / white / silver);
• blue→navy→night dithered fill;
• 32×32 portrait on the left;
• original variable-width pixel font (cap 7, x-height 5, descender 2) in white with a 1-px night shadow;
• types with the voice; ▼ when done.
• Skins follow the era: 4-color light box with dark text at 160×90; 8-bit black box with white frame and an 8-bit portrait; 16-bit/present blue (it fades with the present and turns vivid when color returns).
• Battle messages go in a thin top window. Every box stays ≥ 1.8 s and ≥ voice + 0.6 s. The next box cuts the previous one. The .srt is exported from the same window.SUBS array.
• Title: two lines, 2× font, 8-neighbour ink outline, white→silver→steel gradient by row, Bayer-dissolved in and out. End card: gold title, blinking ▶ CONTINUE, style name, LemoLab × Claude Opus 5.5, and the red scarf drifting across once. The LemoLab sign-off belongs to this library's demo only: a user's film carries no LemoLab credit and no copy of this card.

Pitfalls

• Rank-based palette mapping crushes everything to black: with many dark colors in the master palette, a quantile map puts half the scene in the darkest step. Map by luminance with a gamma (lum^0.8).
• Collapse subsets without warm hues turn a sunset solid red on the first step. Keep orange, pink and plum in the 16- and 8-color sets.
• 8-bit palette without a dark green: night grass turns blue. Generic brightening around a fire makes grass neon green. Use a warm remap.
• Post-quantizing a full-color scene to 4 shades is mud. Draw 4-color scenes natively with 4 known indices at half resolution.
• Hair drawn as a smooth dome reads as a helmet. Back hair with alternating single pixels reads as sawtooth noise; use 2–3 big spikes. A cream tunic reads as bare skin. A staff held in the front hand crosses the face in side view; hold it in the back hand behind the body. A back-mounted sword crosses the front of the torso; use a hip scabbard.
• A dark plank door reads as a jail. Use recessed panels with bevels lit from the upper left, studs, ring handles and a tympanum. Draw the closed door's centre seam dark, not light.
• Negative modulo: Math.floor(t*12) % 4 is negative when a phase offset makes t negative, and it indexes undefined. Use ((n % m) + m) % m.
• Homophones: whisper hears "inn" as "in". Accept it through the asr field; the subtitle disambiguates.
• The dialog box covers the bottom 25%. Put the floor line at y 128 so standing characters stay above it.
• For a match cut on a protected color, compute both screen positions. The demo's scarf is at (197, 104) in both eras.

Build notes

styles/pixel-rpg/demo/
  px.js        indexed framebuffer, palettes & LUTs (full/nes/gb4/faded/c16/c8/c4/c2), dither, mosaic
  font.js      variable-width pixel font      ui.js        windows, dialog, menus, file list, status, save
  sprites.js   rig + ASCII heads, scarf tails portraits.js 32×32 portraits + expressions
  props.js     crystal, halo, pedestal, door  memsprites.js 4-color kid sprites
  scenes.js    corridor (parallax), door tilt, LIGHT/DARK index lighting, torches
  memscenes.js village (160×90), campfire (8-bit), battle (16-bit), thumbnails, title, end card
  main.js      director: shots, transitions, palette timing, EV (sound events), SUBS
  timeline.json single source of timing (music, picture, mix)   lines.json voice script
  music/score.py original chiptune from timeline.json            mix.py foley + voice + ducking
  sheet.js     model sheet (?sheet=1)          tools/subs.mjs srt export      build.sh one-shot rebuild

1. Write timeline.json first: sections, BPM, downbeats, hits, silences, the collapse steps. Music, picture and mix all read it.
2. ?sheet=1 → model sheet; ?frame=corridor|door&lut=faded → environment self-check frames before laying out shots.
3. core/tts/tts.py → asr_check.py (all OK), then compose music/score.py against the timeline (a parallel sub-agent works well).
4. node core/render/still.mjs demo --range 0.3:54.3:1.5 → sheet.py overview; check the key moments frame by frame.
5. events.mjs → mix.py → tools/subs.mjs → video.mjs --workers 3 (1308 frames in about 20 s) → mux.sh … 24 0.
6. sh demo/build.sh reproduces everything from scratch.