Really only other mobile game I play besides Era is Bullet Force. It's a F2P FPS online shooter. Sort of like COD for mobile devices. Their are some guns you can get with the gold currency (currency you obtain by spending real money on) but a majority of the in-game credit guns are better. It's not that hard to farm up either. I recommend giving it a shot if you like COD, or fast action FPS games in general.