I'd recommend writing to itch.io support and requesting a refund or a solution. I didn't because I was afraid too many days would pass, and I didn't want to get bogged down in an email exchange for $5, but if you want to, go ahead. A user tried to help me, as you can see, but it didn't work, and I also tried contacting the developer, but that didn't work either.
It seems like they've abandoned this page or something, I don't know, because they do announce the patches, or maybe there's an error in the files uploaded to the site. Try to get a refund if you're interested, and if you want to get the game, I'm afraid it's only available through Patreon.