But it seems like the mix is lacking in the high frequencies. It's kind of muddy, especially the noise percussion. Also, the bass is kind of weak. It's really low and bassy, which is good, but it doesn't have enough higher frequencies, and that's a shame, because the bass is pretty sweet in this tune. It just doesn't stand out enough. I'd start with a typical NES style triangle or sine or something similar, and go from there.

I don't know, though... I don't mind the repetition, but it just seems a bit too long for being so repetitive. It doesn't have that elusive quality that drags you into a repetitive piece and keeps you coming back even though it never changes.
I know how hard it is to delete things to change the length of a piece, so I'd suggest having something unique about each section. Maybe add an extra instrument to act as the "narrator"/vocalist, who will make exclamations and "adlibs" over the track as it goes along.