Hey! Sorry for the trouble everyone.
It seems like Mike's solution should work for Catalina. Thank you for sharing it!
Here are some more tips:
1. If you don't want to use the command line to change the permissions on the app, you can redeem the Steam key and launch it from Steam. It should still launch fine from there.
2. If you want to select the window / resolution settings before launching the game, you can:
- Hold the option/alt key at application launch or...
- Run it with the command line argument "-show-screen-selector"