Really nice game. I like that it's not a regular platformer. I think the game would benefit from a few particle effects and such, though... for example when duke dashington runs into spikes it always surprises me that there's no blood from it. Also when he hits a wall... it seems only fitting that there should be at least a little bit of dust particles coming off the wall.
Still an excellent action/puzzle game! Keep up the good work! :)