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Games & Simulations

Race three models to build a Counter-Strike clone

InstantDB had Codex, Opus, and Gemini each try to build a multiplayer shooter.

Done withCodexGemini

What they did
Each model (Codex Max 5.1, Opus 4.5, Gemini 3 Pro) ran in its provider's CLI on a top-tier plan with default settings. They got about seven consecutive prompts. The first four built a local three.js shooter: map, enemies, gun, sounds. The last three made it multiplayer with Instant presence and topics, then added a database-backed map list. The humans mostly pasted errors back.
How it went
All three ended with a working multiplayer 3D shooter and no hand-written code. Opus won the frontend, Gemini the backend, and Codex landed in between. Opus got stuck on React useEffect bugs until the engineers read its code.
Worth knowing
Gemini had fewer errors, possibly because it ran the build step repeatedly. Expect to paste errors back, and expect to read code yourself when an agent gets stuck.

Try it yourself with Codex

Build a simple multiplayer first-person shooter inspired by [Counter-Strike] in the browser using [stack, e.g. JavaScript and a realtime backend]. Include movement, shooting, health, and [number] players in one room. Finished means I can open two browser tabs and play against myself, and you list what's still missing.

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Discussion on HN · Nov 28, 2025

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