Unity executables require the Windows libraries/dll's to run, so only uploading the exe results in the problem you're seeing. Next jam if you're using Unity, package your exported folder as a zip file for uploading. I would say upload it for this one but I believe Kenney would disqualify that as it's after the submission deadline :/
Viewing post in Hungry alien jam comments
thanks i just noticed that there are 2 comments on my game. I have made a new page (not for the jam) and put the correct files on that page https://dennis-krok.itch.io/hungry-alien. nice game you made btw