Hi! I'm sorry this is happening. I have no control over the backend of Itch.io I would suggest posting your issue over here:
https://itch.io/board/10023/questions-support
Are you downloading from Windows 10? There was a user with a similar issue for another game of mine due to his IP / connection. I was able to help him but STARDROP's too large for me to host anywhere. (I cut that game up in parts and hosted it myself)