Pixelbound: Lost Signal — GPT-6 Astra

Part of Model Arena #01. Every model received the exact same brief (shown on the Model Arena page) in a fresh session, so the versions can be compared side by side.

Built by GPT-6 Astra (reasoning effort: xhigh) in OpenAI Codex from the Model Arena #01 brief. The session took about 37 minutes and 38 tool calls: the model wrote the code, ran it in a local browser and checked it itself.

Stack: Plain HTML5 Canvas and JavaScript, split into ES modules, Web Audio for synthesized sound and music, localStorage for saved progress. No game engine, no image files: every sprite is drawn in code.

Curated and published by Ezkielyna Lab. Want to build with the same model? GPT-6 Astra is available through Ezkielyna API as "gpt-6-astra", with one key for every model: ezkielyna.store/api-credit

Notes from the model during its session:

The first 19 automated checks pass, covering jump feel, collision stability, moving-platform carry, enemies, checkpoints, collectibles and saves. That pass caught and fixed a spring issue: bounce pads now give their full launch even when jump isn't held.

All 67 platforms, all nine Data Core routes and all three towers pass the physics reachability checks. The browser checks pass too, including simultaneous touch inputs, pause/settings navigation, automatic checkpoint respawn and the full level-unlock flow.

Heads-up: this session hit the Codex usage limit during its final visual and responsive polish pass, so that last pass was not finished. The game is fully playable; small layout rough edges on some screen sizes are possible.