Ahh, thank you for bringing this up. Someone ran into this a couple weeks ago, but I haven't really known the best way to handle it here on the itch page. I think ultimately I'm going to have to discontinue Mac support, unfortunately.

The frustrating part is, it technically could run, but Mac's security stuff doesn't trust the app. Because I don't have a Mac myself, I'm not able to build the program in a way that Mac will trust it, or even give users the option to trust it, as I think it did in early versions of OSX.

There is theoretically a way for you to run it on Mac, but you'd have  to do some terminal stuff to remove the OS's quarantine on the file. I've attached a screenshot from this Godot game engine page that shows how to do that. However, that's a huge pain & I wouldn't expect anybody to go through all that just to run the program, which is why I'll probably have to remove the Mac option.

One hopeful possibility for the future is--I'm planning to go Open Source with this project at some point. Once it's Open Source, you could get the Godot project files and build it yourself, and it should run just fine. If you like, I can make a note to reply on this thread whenever that happens, so you get a notification!

Thanks again for posting this, and sorry I can't get it to work smoothly on your machine!
Nash