just read the rules, but I don't really get how you are supposed to make sure that everyone obeys the time limit

You can't, unless you wanna go through someone's commit history. It's the bane of all jams. Just be honorable imho.

We are working on an honor basis. Plus there's a curse in place if you fail to comply, you'll never produce a fun game.

Personally, I feel like the challenge is to do this within the rules. If you win but cheated, then the only one you really cheated is yourself, because the *point* is the 7 day restriction.