The download should be working as intended. This is the first I have ever heard of a report like this.
I'm very sorry for wasting your time on a report that could have been avoided if I had checked my computer first.
I've downloaded the game on my phone instead and it worked perfectly fine problem is indeed my computer as I thought in the first place but I was just confused as the files had never been empty when I downloaded itch.io games before.
Still I'm terribly sorry for wasting your time on a report just because of empty files. Thank you for responding to my report/post and have a nice day/evening.