Could you be able to fix the Mac app? The game says I am missing data when I click on it normally. I have to right click and open the executable file within the app. 
Hi. Could you please screenshot where and what you rightclickig?
Check this please https://itch.io/post/499554
if above will not help, in game window you screenshoted above open console with ~ or shift+esc key, type path, press enter, screenshot it, share here and type quit, press enter.
Also you may try download and use QtLauncher app if you still dont.
I right click the app and hit "show package contents, then click the contents folder, then to the folder that says Mac OS then this file right here allows me to play the game. I will see if the solutions work
Edit: I see one of the solutions is the method I use to get it to work. Just seeing if I can fix it so I don't have to do that.
Rexuiz.app.zip - here is a link to quick fix. Could you please backup you current Rexuiz.app folder, and place file over it? It have to fix that Catalina issue with relative paths in game
Btw, regarding this one -> Issue on catalina if your version of catalina outdated, you may fix it just updating to latest.
oh yeah, sorry for not responding, was busy with something. Didn't really fix it. Oh well, still works regardless.
Just add this info for people with Sierra/Catalina (I have a friend who has Big Sur but he didn't have a problem clicking on the app)
- right click app and click "show package contents"
-Go to Contents > MacOS
- Click file named rexuiz-dprm-sdl