Mechanically interesting platformer. The various environments went a long way to add interest to progress. A little detail and some background music, and you'll have the next Yoshi's Island :D
Because the player jumps so high, you may consider constraining, damping or interpolating camera movement to smooth out the visual experience. Using 'J' and 'K' were a little awkward, and might benefit from being additionally mapped to the left and right mouse buttons.
That said, a good and challenging platformer. Well done, and good luck!