Just keep in mind for other games if you buy them while they're on sale you can only access the files of what you spent (if a game is $10 and its on sale for %50 off you'll only be able to access files that require you to spend at least 5 dollars)
This is not true, if there is an issue with that you just have to message Itch.io and give them your e-mail. You can do that by clicking "i already paid for this game"