What they did
Cheung built the visual world of Old Days Millennials, a game about growing up around Y2K, in Codex. A GPT-6 Astra session on extra high reasoning acted as coordinator: it read Cheung's feedback, set priorities and opened fresh work chats running Sol models with GPT Image 2 to produce the images. Cheung chose separate chats over hidden subagents so Cheung could drop in and watch the briefs, candidates and revisions. The agents kept handoff notes on accepted designs, which reference file supplied what, and what was left. Claude Opus 5.5 wrote the game code and background music separately, and Codex later helped write briefs for Suno and distribute the music through its browser.
How it went
Style took a few rounds: the first two Hong Kong comic directions came out too cute, then too much like a gangster comic, before a softer take landed. The agents eventually caught and fixed a recurring error on their own, a single earring jumping to the wrong ear, and kept checking it in later work. Repeated revisions blurred the small faces in full-body sheets, so Cheung stopped the work and had clean face and outfit references rebuilt. The project produced character sheets, adult versions, comic pages and an OST cover. Cheung gives no cost or time figures beyond three weeks across several games.
Worth knowing
Without written notes, an instruction like keeping a rejected variant but not using it gets lost between chats. Tiny faces degrade when each new image inherits from the last, so keep a fixed, clear face reference and change outfits against it. Cheung plans to generate head and body separately next time.