Very interesting concept! I especially like how slamming into a platform forces it up a size; really adds a bit of extra strategy to the platforming.
One thing that may have been nice would be a way to see which walls had spikes hidden in them; a couple of times, I died because I just didn’t know they were there. Also, I think I managed to exit the boundaries of the level at one point (wall jumped out of a hole in the top and then slid down over the edge).
Well done on the game!