Very nice concept, it's a bit too punishing maybe make the hazards a bit smaller to start with. I also think the foreground shader is a bit too much, maybe try slowing down the flicker.

Can't flip gravity while falling.

I like the screen effects, and the overall feeling. One thing that felt odd was only being able to change gravity direction when you are actually standing on a platform. I guess it has to be like that, or you could effectively hover at will, but it nevertheless felt a bit like an arbitrary limitation, from the player point of view.