Nice graphics. I love the parallaxing city in the background.
I know the jump height has been addressed in previous comments. It was a big issue when fighting the blue guy in the ice caves. I don't know if he is killable, since I wasn't sure if I was hitting him, and I kept hitting my head on the ceiling.
Overall it was very ambitious, and it looks like you have a good base for tuning and refinement. Great job.