Tedious. This game has so so much potential! If the object is to force players to purchase items, it's wildly successful. Not a pay to play game, but a play to win game. And win is said tongue in cheek. The special levels require so much energy for little reward. It's something like a 5000 to 1 ratio for energy return. Ridiculous. Great graphics, smooth play, interesting levels, nice mini games. Poor to laughable energy generation and output requirements. In short, skip it.