A nice and fun game, thank you! A special plus for the overall atmosphere: the graphics and audio set the perfect mood, as if you are really diving to the bottom of the ocean and your oxygen supply is limited :)
I will also note the cool visual solution with a decrease in the amount of light when you go deeper: like in real life.
The controls seemed a little too sensitive to me, so it took some time to get the hang of it. But overall - a great concept and result!