1) extract the art (including audio and other fixture data)
2) instrument some kind of parity-checker / validator against the base game
3) /loop to have an agent rebuild the entire game the way you want
The hard part is 2) and push comes to shove you could probably pay a part time high school intern to laboriously go through the game and make sure it is a faithful recreation.
IANAL, art assets are the IP of the creators. It would certainly be illegal to host or otherwise distribute the art assets you do not own. I see the industry coming down HARD on this form of reverse engineering if only because it is so easy.
[1]: https://simonwillison.net/2026/Oct/28/vibe-game-development/
EDIT: Shit, this is really going to incentivize game-streaming platforms (a la Google Stadia) and disincentivize gaming clients.