I think I'm missing something. because this is a demo correct? That's what the files are labeled as, and I was asked for a donation, So there has to be something I'm missing. You should only ever pay for a full game. The entire point of a demo is to allow people to play BEFORE buying the game. So they can see if they like it or not. It's definitely possible this is a full game, and the file names are old. It says nothing about being a demo on this page I dont think. It's just the file names. If this is an unlabeled demo that's a whole other issue and problem.
the donations are optional, no one is being forced to give them money. also in this case it's not really a demo or the full game, it's just the first chapter. a lot of itchio games release in parts. it makes it easier on the dev teams while also allowing players shorter wait times for playing than just demo to full game