I'm also having this issue, tried both PixelDrain and Moon Loom.
Dont think its for mobile. Only Windows PCItch.io app FAQ might help you on why you cant play it with the app.https://itch.io/docs/app/faq
I should specify that I am on PCs app for it but its still unable to download.
if unable to download, then probably not supported for the appGuess you have to play it from the folder instead
