I also got stuck on the spike section for a bit since I found the wall jumping a little confusing, having to press the opposite directional key to jump off, but I cleared it eventually. I'd suggest having an easier area that utilizes the purple ability for the player to get more used to it but is less immediately punishing, and then ramping up difficulty to the stage you have. Also, having to wait for the mutation after every attempt took away from the fun a bit. Having a checkpoint state that has your character ready for the next attempt makes gameplay smoother.
I was wondering, was the sticktoe ability hard to program? How did you do it?