Cool idea
I liked the feel of the game, however, there are a few frustrating points.
1) why cant the up arrow be jump :( 1 handed motions are always easier then 2 handed motions
2) air physics. when an object slides off a ledge, it looses its momentum do to the pull of gravity. you would never actually slide of a ledge, flying into a wall of spikes. (sir Isac forbids it) (just look at a snowboarder flying off a cliff, almost immediately strait down)
again, cool game, just needs a little fine tuning.