The same happens on PC.
I tried to install it via the itch.io app and it said that the game files are hosted on an incompatible 3rd party website.
This has been mentioned to the creator multiple times though, so I'm not expecting it to change. [Last time i brought it up they said they weren't doing an android version and that's why.... but I think they were confusing the desktop client itch.io app for one on mobile devices. This issue is with the official itch.io client on PC/Mac that you use to install, run and update your games all in one place.]