when the download reaches 100, it says that crashed or it doesn't reach the end at all. it says file not found.
Unfortunately, that sounds like something we can't fix on our end. I just tested downloading the windows version of the game and it worked alright, so the file is definitely there and itch.io should still be working just fine.
A download failing to finish could mean an overzealous antivirus, or problems with the browser you're using. Here's a slightly old guide from Itch.io that might be able to help, but unfortunately it sounds like whatever problem you've got is something that can't be fixed on our end.