This was really fun there was a sense of exploration that I wasn't expecting. The camera was an issue as you said there were times I wasn't sure what was below me. I'd have to try it and compare before I could say if locking the camera horizontally is for sure better but it seems like it would allow the player to have a better sense of his or her surroundings which I think would be good but I also wonder if it would hurt that feeling of exploration I got from the verticality of the levels and not knowing what I would find if I went high or low.
Also great level design. I liked your use of the bounce pads and the spinning maze (for lack of a better word) was really cool.