Claude Opus 5.5 vs GPT-6 Astra: what the games on this site actually show
People keep asking which of the two makes better games. This site cannot answer that, and this page will not pretend to. What it can do is describe the two piles of games it holds: 13 credited to Claude Opus 5.5 and 20 published through ChatGPT Sites, OpenAI's hosting for GPT-6 Astra creations.
Why this is not a benchmark
The games were not made from the same prompt, by the same person, with the same time budget. Each is whatever an author chose to publish. A model that produced ten rough drafts and one gem shows up here as one gem. Any difference below is as much about who publishes where as about the models.
What the two piles look like
| Claude Opus 5.5 | ChatGPT Sites / GPT-6 Astra | |
| Games | 13 | 20 |
| Usually published on | GitHub Pages (10 of 13) | *.chatgpt.site (20 of 20, by definition) |
| 3D | 8 of 13 | 12 of 20 |
| Open-source licence | 4 of 13 | 3 of 20 |
| Work on a phone | 10 of 13 | 17 of 20 |
| Single file, works offline | 3 of 13 | 5 of 20 |
What the difference in publishing tells you
The Claude games mostly arrive as GitHub repositories with a README that names the model and often the prompt, so their credit is easy to find and easy to quote. The ChatGPT Sites games arrive as a bare address with no README; the hosting is the only clue to how they were made, and we say plainly that ChatGPT Sites predates GPT-6 Astra, so a game there is not proof it came from Astra. That difference in paperwork is the most reliable gap this site can see.
Where to start playing
If you want to see what a single long brief to Claude Opus 5.5 can turn into, start with Turbo Kart Rally, NOVA LANCER or Crab Dash. For the Astra side, the Astra index lists every GPT-6 Astra game we could find, and this note explains how those are built. The full Opus list is in 13 games made with Claude Opus 5.5 you can play in your browser.