The calm and somber, yet somewhat reassuring water theme from Super Mario 64. Probably best fits traditional Mario-y water levels, perhaps with a focus on exploration. Insert a joke about the Wario apparition here.
I think this port is spectacular. The only feedback I can give might be subjective. Dire Dire Docks was a very engaging song for water levels. Here I think channel 1 and a bit of 2 come on strong for the main riff where in SM64 it was a calming sort of instrument.