I'm also experimenting with it more and more. Now I'm trying to create a 2D side-scrolling shooter with it, running in the browser. When it was relatively small, it did a good job. As the codebase and docs/ files that I'm using get larger it starts hallucinating, especially when the context gets at about 50% usage (Codex w/ gpt5.5). As in, it'll literally forget to update parts of the code.

e.g, I change velocity of player to '200' and of bullets to '300', and it only updated the bullet velocity. Then told me the player was already 'at the correct value' even though it was set to 150. Things like that.. :)