Hi there, did you make sure the download was completed successfully? I think the download was incomplete, and thus displaying such an error message.
I believe so. I have downloaded it a couple times now,(deleting it each time before downloading it again) one of witch I sat and watched the download myself. Yet, every time I get the same message. Also, I am not sure if it is important but each time I have downloaded it it claimed it would take several hours to download but it finishes in under 10 minutes.
Ah, it's definitely the download issue, I believe. Can you check the zip file and see its size? If it's less than 900mb, it's definitely failed download issue.
Can you try using itch.io app to download the game? (It might help in downloading the game)