Claude builds full 3D browser game from 2024 tweet in one session

In August 2024, Willison had tweeted screenshots showing GPT-3's text-completion output for "a detailed product description of a computer game where a team of raccoons go on heists" and DALL-E concept art of a video game screenshot with raccoons on a heist. Two years later, on August 5, 2026, he decided to revisit the idea: could Claude Fable 5, running inside Claude Code for web, build a full, working game from those same artifacts?

Willison's setup was practical: he created a new GitHub repository and used Claude Code's integration with GitHub to push changes to a branch. He then configured GitHub Pages to deploy from that branch, so the game would be live and accessible within 30 seconds of each push. This workflow meant he could preview Claude's work in real time without leaving his phone—he wrote the entire prompt in the Notes app. The prompt asked Claude to build a 3D browser game with mobile-friendly touch controls, to use OpenAI's image generation API to create textures for 3D models, and crucially, to "work independently—do not ask me to make any further design decisions." He also asked Claude to "commit and push as often as possible" and to maintain a notes.md log of changes.

Claude's build process showed autonomous decision-making at every level. It started with an index.html page and vendored a copy of Three.js, then wrote its own gen_textures.py script to call OpenAI's gpt-image-2 API and generate textures (metal, concrete, wood, grass, asphalt, brick, and a starfield). It used Playwright to take screenshots of its own work at different viewport sizes—desktop, portrait phone, landscape phone—spotted that the raccoon was invisible on mobile, and fixed the issue. It generated a title screen by crafting a detailed image prompt for gpt-image-2: "Video game key art, low-poly 3D render style, moody nighttime scene: a cute low-poly raccoon wearing a tiny black burglar mask sneaking on its hind legs carrying a glowing gold coin, next to a tipped-over metal trash can, suburban house with warm glowing windows in the background, deep blue night, full moon, fireflies, cinematic rim lighting, charming heist caper mood."

Then came Claude's most striking addition: the guard dog. For night 3, it created a low-poly brown hound with a spiked red collar and wagging tail, implemented it with procedural sphere and cylinder geometry, and programmed behavior where the dog wanders between random spots and, within 12 units, catches the player's scent and tracks by smell (line of sight irrelevant, indicated by a 👃 emoji and barking). The dog gives up if the player opens a 17-unit gap. Claude tested this using Playwright, teleporting the player next to the dog and running automated playthroughs to verify wander, track, and caught states.

The final game is playable at the GitHub Pages URL. The player is a masked raccoon sneaking out of a dumpster hideout into a moonlit cul-de-sac. The goal each night is to collect coins, gems, rings, donuts, fish, and (on later nights) a rare golden TV worth 120 points, carry them back to the dumpster, and bank them before dawn. Each collected item visibly stacks on the raccoon's back and slows movement. Difficulty escalates: night 1 has one guard with a flashlight, night 2 has two guards, and night 3 adds the scent-tracking hound. A police cruiser sweeps the street with headlights, homeowners randomly peek out of windows, a seagull dive-bombs unclaimed loot, and pizza slices trigger a 6-second speed boost. Win ranks are TRASH PANDA ⭐, CAT BURGLAR ⭐⭐, and MASTER OF DISGUISE ⭐⭐⭐; the best run is saved to localStorage. Mobile gets a dynamic touch joystick (appears wherever you touch) plus a DASH button; desktop uses WASD/arrow keys and Space.

During testing, Playwright caught two real bugs: the canvas was rendering at 2× size on phones because a cssText assignment was overwriting Three.js's inline sizing (desktop DPR-1 tests had masked it completely), and the win screen's star-rating div had inherited full-screen .stars CSS from the title screen, silently swallowing taps on the "next night" button. Both were fixed and regression-tested. The game uses a procedural WebAudio soundtrack (sneaky walking-bass jazz plus all sound effects) and zero audio files. All textures and the title art were generated with gpt-image-2 and committed as static assets, so the deployed game makes no API calls at runtime. The full build log is available in notes.md, and Willison's transcript of Claude's code decisions is publicly accessible.