Heyy, I'm on the Mac and have also faced this problem. Luckily, I've found a way to get in the game (for now). First, in the game folder, right-click on the .app file (the one with the Ren'Py app icon) and press 'Show package contents'. Go to the 'Contents' folder, then 'MacOS', and finally run the executable file titled 'WHODUNNIT'. Hope this helps!