I thought it was a novel spin on the Metroidvania concept to have your abilities also act as keycards. However, I think you probably could have just gated the player off with a challenge they could overcome only after they got the ability anyway. The concept was pretty neat, though I would love to see more abilities added. Also, run didn't feel like a super useful ability to get, since you could just spam air jump to span long distances anyway.
The art is pretty good, but some portions of the level are a little dark for their own good. The character design is great, and I'm super impressed that you were able to make fairly good looking animations in such a small time frame.