Very very solid!!!
Graphically it was extremely charming. The first little swap up of the darkness to light when you go invulnerable was actually really great. For the most part, you do a good job of drawing players towards where they need to be, but a few levels do have branching paths that I don't think help the experience. I absolutely wanted to save the skeleton. I got to about level 8 before I had to put it down, and other than the thinner stairs being a little finicky, I really loved a lot of the choices you made. Keep at it!