Loved it!
This one is the clearest winner as far as polish, graphics, and complete experience goes - to me anyway. It feels like the complete package. The artwork is cute and I love the style.
Everyone's probably gonna comment on the camera controls... I think we expected the Mario64 camera and got something that was a bit "off".
This disconnect of camera from controls was a bit disorienting at first. It would just be cool if it would follow the fish facing direction much more directly.
Maybe run the same function that the alt-key fired - every frame. And speed up lerps / tween parameters.
But hell yeah! A main menu and good audio to wrap it all up. Last suggestion I could imagine is a childrens / relaxation mode without the air-running-out-feature. I died right before I hit the water - coming off the stairs / deck.