Okay! It should be working now. I tried it with a computer without steam/any other storefronts and it worked fine. Please redownload it and let me know if you still run into any issues!
Thank you so much for letting me know!
Loaded it up real quick and it both worked and retained my progress, so yay! Thanks for taking care of that so quickly.
BTW as a heads up when one tries to download this via the itch app it initially only lists the "nextfest" demo and you have to manually select show all downloads to find the full game one and when you select it a warning pops up saying that it isn't tagged for any platform but it might still work on Windows (which it does). My best guess is that because it seemingly isn't tagged properly the app is half-hiding it? I included a screenshot so you could see what it looks like: