Cash grab that is unsustainable at higher levels. I'm decent at this game: got to level 6 in the "tower" module, and got through level 16 in regular gameplay, but can't afford to get enough stars to unlock level 17 with the economics of this game (not w/o pumping actual cash into it, and maybe not even then). They made it get hard enough at a certain level that even the best players will have to pump more cash into it to continue to progress than if you just purchased a $70 console game.