This is actually a pretty decent game! Reminds me of something I'd find on Coolmath - it's kind of classic that way. I have a couple things, however. One, the intro cutscene was kind of cliche for me, I don't know, having played a lot of Coolmath in years past might have just made me very jaded towards the whole "rescue the girlfriend" thing. I rather like the aesthetic of it - dynamitewhale might have a good point there with regards to making things colorful, but otherwise it's really nice and a little spooky. Nice touch with the eyes in the walls and the strange water colors. The physics of switching gravity would be cool in a lot of other situations, but it definitely does make predicting and controlling my movement harder. Also hard to figure out how fast I can run one way or the other when there's hazards everywhere that stop me from being able to test that. That's how I managed to get stuck - I found it very hard to predict when I should be pressing the left or right arrow key after I hit Z in order to avoid the spikes, and eventually it got to the point where the combination of that and the arrangement of spikes was just too much to navigate.
Edit: I got stuck somewhere in the first section. I remember that I had to go across the entire level from right to left, dodging some gravity-obeying spikes that rose and fell at the same time as I did (as opposed to them obeying gravity in the opposite direction as me). One of them fell at a different time than the others because there was a recessed area in the ceiling. Hopefully that helps.