Sorry about that! If it says it's corrupted, then it's possible that something went wrong when the file was downloaded and there isn't really anything that can be done about that.
The Time Machine works best for the downloadable PC version. I'm not sure if the issue that caused that was on my end or not but there could be problems because constantly testing that takes up too much time - especially considering I intended the game to be played through multiple times anyway. I should have a warning about that at the start so people don't get disappointed about losing saves
