Let me know if you figure this out! I had the same issue, but have been able to play other Itch games on Mac before.
I never got it to work. Will try on my windows machine this week.
Just in case you still need it, here's the solution for getting it to work on Mac:
1. Open terminal
2. xattr -rd com.apple.quarantine TheDrifter-Demo.app
3. Run TheDrifter-Demo.app
4. Enjoy :)
