Play them in order
How the models were established
Two came straight out of local records: the May 2026 build carries a git commit trailer naming Claude Opus 4.8, and the July 2026 build was made in a recorded session. Session history only reaches back to 13 June 2026 and the older projects carry no tool fingerprints, so the other four were pinned down by checking which models had actually shipped on each build date, then confirmed from memory.
Cross-checking those dates turned up the reason this set exists at all. Almost every build lands on or within days of a frontier model launch: Claude Opus 4 shipped 22 May 2025 and the first game is dated that same day; GPT-5.1’s second wave landed 19 Nov 2025, the date of the second; GPT-5.5 arrived 23 Apr 2026, three days before the third. The kart brief was never really about karts. It was the throwaway test for whatever had just come out.
Line counts exclude vendored libraries and build output. They measure size, not quality: the largest codebase here is not the best game. Every build runs exactly as it was originally delivered. Only the name was changed.