It isn't a standalone app, the game is currently only available as a on-disk webpage. Opening index.html is how you run the game, but that requires you to extract the files with folders in tact, which isn't supported out of the box on android. I am looking into an apk version, but even if that works out, it will not be finished any time soon. I recommend just sticking with the itch.io web version if you can't get it to work