the perfect game when you need to kill some time
I very much enjoy playing this game, the simplicity of its design is pure genius. The puzzles are amazingly well thought out and executed. The progressive difficulty really sets the pace well from beginning to end. Personally, I've only reached level 16 but, from time to time I return to it. The replay value of the game is amazing, wether you've played it before and are picking up where you left off, or are trying it out for the first time.