I can't seem to open the game. Says the application can't be open. 

I had the same issue on Catalina.  I extracted the zip using The Unarchiver instead of using the default Archive Utility.  I don't understand why but, now the game runs nicely.

Me too.

I'm having the same issue on all the games on here :( using big sur. Any other extracting software work with these?

Wow, I can confirm that I had the same issue on the latest release of MacOS Monterey on an M1 Macbook Pro. Opening the zip defaulted to the built in 'Archive Utility' and that resulted in simply

Extracting with "The Unarchiver" was able to properly extract it and run the game (After being annoying and saying 'the dev can't be trusted', then having to control+double-click the file to override that message)

Thanks brsk144 for the fix, something must be weird with the way the app is packaged for the default extractor.