For anyone who happens to try installing this from the Itch client, it doesn't seem to work. Best you can do is install the .exe, then head to the Itch web interface to download the .pck and put it in the same location as the executable.
Re-uploaded the game files as a combined zip - I believe that should make things work in the Itch.io App. Please let me know if it's working for you now, thanks! -🦖
