I wouldn't count on the game continuing to work on macOS Catalina or higher though, it's supposedly a 32-bit application which means it's no longer officially supported by macOS. I suspect this is why the game won't run normally, and whatever trick itch & steam launcers use to get it open anyways may not work forever. Ideally, the devs would release a new 64-bit version of the game for macOS, I bet this would resolve the issue completely.