I like the core mechanics, but I think it could use a bit more polishing to really feel responsive and not frustrating. For instance, I really like the "wall jump" mechanics but it seems a bit impredictible and when you hit a "roof" the gear stop completely which can be frustrating.
I liked the fact that you included a boss! I find a bit too difficult though (couldn't get past it and I'm used to hardcore platformers).
Also, but it is a minor thing, I find it weird to press 2 or 3 to get to the levels, a generic button like enter or spacebar makes more sense to me.
Very nice job!