Nice little game, I enjoyed the wall jump mechanic.
But maybe you should have the keys to move on the side where the player falls, its a bit late telling people how to move after making them move over there to see it in the first place :l Also the walking sound goes of when you are moving in the air too, I'm not sure if that was intentional. And maybe add something to allow the player to know he is taking damage. I found myself standing on spikes and the dog for a while without knowing they were actually killing me.
Great work.