Idk wtf is going on but I can't open the game. I downloaded it to my mac before and it worked fine but now this happens when I try to open it.

It's caused by a quarantine flag: https://discussions.apple.com/thread/253714860?sortBy=rank
To fix it, open a console and type
$ xattr -c <path/to/application.app>
(And yeah, that error message is borderline malicious from Apple's side, just terrible user communication that makes users think the app they downloaded is brolen).
Open terminal.
If you check out this post it has full instructions.
https://discussions.apple.com/thread/253714860?sortBy=rank
The flag is set when a game is downloaded from the internet (and not from an apple approved place like the App store).