SM64 Master Quest -3: Mario Swims to China

A fairly challenging hack featuring exclusively swimming.

Can you swim through the depths of the earth through three main layers, getting progressively deeper, and darker, until you reach china? Perhaps you wish to explore further and find the 6 stars in the depths of the world. Perhaps, you'll even find the bonus level hidden somewhere near the end of the game.

Intended Any% is "Get to the end of the game" stars (aka 0/7).