Ok, so I do run it in 13.1. I will update this as soon as I have time. Right now the game doesn't even produce an error message, neither log.txt nor traceback.txt. It's strange because I also use Ren'Py and don't have this problem, but maybe I use a different Ren'Py version?
Btw: why don't you also make the free version of your game available on the web? Or do you have videos? Cause without videos, it's really easy to make it run on the itch web page.