Ok, I'm completely changing my review after playing for a couple of weeks. I'm pretty obsessed with this game, but it can be pretty hard to play on some of the levels because it uses so much energy to play, and you run out very quickly. Buying the energy with real money is VERY expensive. Prices start at $4.99. It can be frustrating. The puzzles r fun except when u get completely stuck and can't find a walk through on you tube.