How are you extracting the archive? It's a RAR5 compressed file, so you may need to use a different (or more updated) tool.
Actually, I managed to get it working. It was odd: I couldn't extract it via Stuffit, and I couldn't run the game through Itch. But downloading and installing the game through Itch and then going directly into the files, finding the .jar and running that seems to work.
A bit of a weird solution, but it works, and the game runs with no hiccups, so I can't complain. It's pretty fun so far, well done. The 'bad endings' can be a bit sudden an unpredictable for a new player (which can cost a lot of time without frequent saves) and can feel a bit unfair, but overall the game is solidly programmed, nicely done.