Oooo, so cool. I don't think I've ever seen a game mechanic like this. Supper original and fun. Truly chaotic. But. There is a small problem. The Depth. You can't really see how far an object is from you, this added with the fact that the movement feels wonky in a way, makes the game unnecessarily hard.
A small suggestion. When holding down your mouse button to breath in, it would be great if you could see how much air you have breathed in. Another thing you should consider adding, is a depth meter. If you don't make it to the bottom, it would be great to see how far you've come.
However, the art, the movement mechanic, and the music, put together. Makes a great game! :)
I think it could be a truly outstanding game with some minor improvements!