The audio is top notch! The attention to details in the way the music raises and lowers the volume really made me get "immersed" into it!! (pun intended hehehe)
The controls of the frog was really interesting, I just think the camera could pan a little more "ahead", because it is already hard to be in the depths not knowing if you'll find a dead end, a little more "look ahead" would feel a little more fair while keeping the difficulty almost where it already is. Also, maybe the "shift" could spend more oxygen? That's a design tradeoff, it would favor more careful gameplay instead of the "rush", so maybe it doesn't fit.... but I wanted to share the idea anyway :)
Congratulations!!! I really really liked the vibe!