a very pretty game!
1, pack your game with google closure compiler, so game loads faster
2, the camera needs a little smoothing, you can use simple mechanism such as LERP, sharp camera movement especially when jumping puts strain on the eyes
3, its very hard to perform high jump on the spring platforms, maybe you can change that by allowing holding the jump key to perform high jump on landing?
4, movement needs a little acceleration, without acceleration, turning around is too sharp, and its harder to make fine adjustments.
my 2 cents