This is one of the better games Ive played on IOS for quite some time. It follows pretty much the same formula as similar games, but there seems to be more combination options and upgrades. Purchased DLC is present but not *constantly* in your face like other games. My only complaint would be the power usage, which can be adjusted in the settings menu for video quality and sound. My phone has been *plugged into the wall* since playing, with nothing else running in the background, and its drained my battery. I only had to stop playing once my low battery alert came on, and it being plugged into the wall...
Its a great game, just take it in moderation.