Claude Opus 5 Generates Playable FPS Game with 3-Paragraph Prompt on July 25

On July 25, Matt Shumer, maker of the Claude-assisted game, posted a video of a fully playable first-person shooter that Claude Opus 5 built from a remarkably simple prompt. The three-paragraph instruction told the model to build a game at Call of Duty level, fan out subagents to tackle components individually, and keep looping with a separate critic until the output held up against real footage in a blind side-by-side comparison. No external assets were used; the finished build contains roughly 55,000 lines of code across 11 subsystems.

Others have since replicated the result. James Altucher ran the identical prompt and reported spending about 10 hours and 1.3 million tokens on Opus 5 to produce Operation Blackout, which plays free in the browser. A developer using OpenAI's Sol 5.6 Ultra with the same prompt also succeeded, as did Leon Lin, who reverse-engineered a detailed 20-section prompt and used plain Opus 5 to create Dust Corridor.