Great concept, great artwork ( I love the little knight!), and fairly well polished! I really liked the powerups and the fact that you can only hold one at a time makes for a very puzzle approach!
Recommendations: Perhaps lock the player character's facing for a short period of time when the player presses. There was a lot of dead time and I think having the ability to move multiple times in a single direction would have been useful (especially in those straight paths). Alternatively, if the levels emphasized clockwise rotation to allow 2 movements at a time (with a loop, coming out of the other side), it would decrease the down time.