Heyo. I didn't know this was up already! I guess I don't have much to say about this in reply except that a "water main" is a kind of big pipe, hence why I thought it an appropriate name for music from the level you take a big pipe down into. Also, in the first Super Mario Bros. it was already in a 6/4 (or 3/4) metre. It didn't become 4/4 until they redid it for Super Mario Bros. 3. (By the way, 6/8 usually means two triplets per bar, which really doesn't describe this piece at all.)
As for comments on the guitar work, I really, really don't deserve any comparison to Satriani, but I will agree that the guitar is very noisy and rough (the way I hoped it would sound ). I don't know what people find so odd about the drums (maybe the snare processing and distortion? maybe it's just the fact that it's an mp3?).
Anyhow, thanks for all the comments everybody!