Can't choose my username. Instead it just set it to the first part of my email (I don't use Facebook for mobile games and that was the only other option). It uses your name and profile picture from Facebook if you choose that option, meaning your randomized opponents could just go find you out in the world. Plus the game is laggy. These are my biggest problems with it. If there are more problems I wouldn't know, because I uninstalled this after five minutes.