AI investor Matt Shumer posted a video: Claude Opus 5 built a playable first-person shooter from scratch — zero external assets, ~55,000 lines, everything generated inside the browser. The prompt was three paragraphs.
That flips the vibe-coding rule: *specify criteria, not adjectives*. Shumer wrote "level of the latest Call of Duty" and let an Opus 5-built critic define what that meant. He calls it a Gauntlet Loop — a real inspectable bar, isolated subagents, a harsh critic who never sees the builder's reasoning.
Skeptics assumed hidden manual work; Shumer published everything. Others confirmed it — the same prompt works on OpenAI's
Sol 5.6 Ultra too. Honest caveat: in a blind test against real CoD footage, his game never won. The real thing took every round.Decrypt