The file download, unfortunately, is only the executable. It needs the rest of the files to play it! Idk if this is your first gamejam, but usually you compress the full files that you get from your build and then upload that compressed file. I'd try reaching out to the hosts and see if they will allow you to upload a new file someway? Wish I could give it a play.
I will report it and hopefully the hosts give you a chance to reupload, keep an eye on your email!
If you'd like to give my game a play, any feedback would greatly be appreciated! It is multiplayer, so if you can play with a friend/s it'd be better, but its not necessary.