Simon Willison described four browser games he made with Claude tools in a post published October 28, 2026. He said none took more than four hours of his own work, while Claude Code ran for many additional hours. The projects followed different paths, from a single prompt to extended iteration and playtesting.
Willison called his approach “vibe coding,” meaning he did not look at the code. He described all four games as HTML-and-JavaScript projects that run in a browser, and named GitHub Pages and Cloudflare Pages as typical options for static hosting.
Four games, four workflows
| Project | Reported workflow | Iteration or playtesting |
| Tree Appreciator | One prompt in regular Claude chat | No follow-up; a spot-the-difference game with algorithmically generated trees |
| Emberwick | Regular Claude chat | Multiple prompts and playtesting |
| Battle Drones | Claude Fable 5 for early 2D versions, followed by Opus 5.5 | Later iteration and a port to three.js |
| Pumpkin Farmer / Quarter Sun Cove | Opus 5.5 Ultracode | Still being iterated on; Willison was not yet convinced by its mechanics |
Tree Appreciator was the one project Willison described as a one-prompt result. Its tree collection is presented as a herbarium. Emberwick, a top-down fantasy role-playing game, includes a village, characters to talk to, connected basements and a mountain cave with a sleeping troll. Willison estimated that its story takes about 15 minutes. During playtesting, he encountered a quest problem after a character moved elsewhere following another story event.
Battle Drones is a real-time strategy game in the style of Command & Conquer. Willison said its early versions were playable but not fun; he later used Opus 5.5 to revise the game and port it to three.js. He described features including multiplayer for two to four players, seven maps, replays and random-map generation.
What the four-hour figure counts
The four-hour ceiling refers to Willison’s own work on each project, not the full time the models ran. He said Claude Code spent many additional hours working independently. For Pumpkin Farmer / Quarter Sun Cove, he reported nearly two days of Opus 5.5 Ultracode work and millions of tokens. That project was still in development, and its mechanics had not yet convinced him.
Willison said he enjoyed playing the four games, but his view is a personal assessment. He described his impression of Opus 5.5 compared with GPT-6 Astra as not based on an exhaustive study. The different workflows in his account also show why a single-prompt result is not the same as a game refined through repeated prompts and playtesting.
Another creator moves from a prompt to iteration
A separate demonstration by Prompt Potato starts with a one-prompt comparison of ChatGPT and Claude on a Rocket League-style game. The creator then develops Potato League using a detailed specification, multiple rounds of iteration and 3D assets from Tripo AI, before showing gameplay against a bot. The video is sponsored by Tripo AI, and its demonstration is not a controlled benchmark.
