It says Gun Rounds is damaged and can't be opened. :( I'm on Mac OS Monterey is that the problem?
I found out from another itch.io comment that if you use a different ZIP utility (such as p7zip) to extract the game, it will run once you bypass the security protection for executing an unsigned binary. If you use homebrew, you can just "brew install p7zip" and then "7z x Gun Rounds OSx.zip" or use an actual installer.
Hopefully the other commenter's solution helped, but if not, you could also try the instructions here: https://help.yoyogames.com/hc/en-us/articles/216753558-Mac-app-damaged-when-down...
Long story short, it's an issue because Apple doesn't really like software being distributed outside of their App Store >:(