Ok thanks, ah I think I have a guess for what's happening. I upgraded the Unity version I use to make the game, but that also changes the minimum supported OS version to be higher. Could you let me know the version of mac OS you're using please?
Hmm, actually that shouldn't be the problem, that version should be supported. I'll look into it when I have time (later this week probably), it might be trickier to figure out.
Could you maybe fill in this form please? (You can just put in your email, I haven't set it up properly yet). I haven't got a computer with an environment like yours so it's hard for me to test whether it would work or not, I might need to send a build to you to test if it works. (Hopefully that won't be necessary, but just in case)