In a game that I previously rated, I mentioned that there is a slight difference between a good hard challenge and overly frustrating gameplay. While this game can get frustrating, it falls more on the side of a good challenge that makes me WANT to continue playing and try for the all 3-stars.
There's something fun about the way this game is designed. You can either take the overly cautious route and inch along.... or you can go crazy and just fling your character through the air, continually switching up the gravity. Something kind of just... fun about doing things the second way.
Overall, this game creates a nice challenge that doesn't overwhelm the player. All challenges can be dealt with, any little gripes (you fling yourself off of ledges in tight places) can be dealt with, and completing a level just satisfies. Great entry!