This is what I get for updating Ren'py from Python 2 to 3.
Ironically the paid versions of this game were compiled before I updated, so they don't have this error. I'm uploading the new free versions with the fix.
No more issues so far, I'll let you know if I come across any more.
Respect the dedication and professionalism, especially for a free version of your game. For that (and the rather awesome game) you've earned a paying customer here just as soon as your next update drops.