Super cute graphics already make it great, but the puzzles are very well designed. Since the mechanics are very simple, it's pretty easy to look at a room at get a feel for what you're supposed to do at least roughly, and I always got a great feeling of satisfaction when clearing a room. The mechanic of using bots to hold down switches and as platforms is awesome, but I particularly like having to put one on top of a spring, and then jumping on top of it. Very happy I sat down and finished it.