I liked the concept of this game.

I liked the mechanic of limited oxygen. The consequence of it running out however was too soft. I think a game over would have made the mechanic more weightful.
I also found it hard to orient in the level. I think some landmarks like small rocks could make it easier and also more engaging.

Nice game. But It is missing animation, sound, and  a  instructions screen. I would be very happy if you would play my game.

Cool game :D