Now this is a good game you can play on your phone. So much of what you can find on mobile devices is either pay to win or just not good at all. Just referring to a game as a mobile game has the connotation that it's bad.
This is just a good rougelike and it's crazy that it's completely free. Really fun (and difficult) and one of the best games you can have on your phone that is not an emulator.