To provide some additional data from the Mac side, I downloaded the game and am unable to run it at all, getting an error saying "The application "Gutwhale" can't be opened". This is on Mac Catalina 10.15.2.
I will probably end up playing on my Windows machine, but I also would be happy to help test any future Mac builds!
FYI This sounds a bit like the 'standard error' that you get with a lot of non-app store programs on Mac nowadays. It's usually solved by moving the app from the folder you downloaded it to — e.g. move it to Applications — and then running again. Also, due to permissions/security, you might need to open it via right-click (menu), then "Open".
If you do all of that, you might then be faced with the "quit unexpectedly" message ... or you might get lucky :)
