I think this is a problem with how the default Archive Utility unzips the folder on a Mac. I originally had the same problem, but after I used a different one (Keka) and it worked fine.
This was a problem for me originally but I managed to get around it by using a different program to unzip the file (Keka instead of the default Archive Utility). I'm so glad I did because it's such a nice relaxing game.