I love the NES synth! Definitely helps tie it to the retro sound of the original soundtrack. I think spacing out the melody and the bass by a larger register (an octave maybe) would help clear up some of the muddiness of the sound and let both voices shine through. We lose the bass in the second half, and although you've got a cool riff at that point in the melody I think for the purpose of a rhythm game in this style it might help to keep a really strong bass line throughout. Nice work!