The camera definitely needed to be zoomed out a bit, or maybe make the corridors smaller, i basically spent all the time swimming direction along the ceiling because with that and the pain background I had no other way of telling where I was.
I also feel that the acceleration was a bit off, I understand it's in water so you want it to feel like effort to move around but it was very slow to be able to change direction.
With some movement tweaks and some other background element this could be a really nice game.