When I try to launch it on the Mac, I get an error:

The operation couldn’t be completed. (OSStatus error 99999.)

I haven't run into this problem on Unity games before but apparently this is a problem with older Unity engine games running on Mojave. Looks like I'm having this problem with Imperishable Memories now too (which I haven't tried running since the Mojave upgrade). From what I'm finding online, Unity 2018.2.9 fixes the problem, although you might consider going all the way to 2018.2.20 which has a bunch of other bug fixes too (while still maintaining compatibility).