This is probably the most under-rated Mega Man song ever. Aside from Strange World in Mega Man 9. The game itself, Mega Man 4, oh GOD it's hard and I never got CLOSE to this point in the game. I hate that game SO much. But the MUSIC, OH GOD the MUSIC, is AMAZING. And this is my favorite track, remade/covered as accurately as possible in 8-bit.
If you haven't heard it, go here:

http://www.youtube.com/wa tch?v=qqDmmQxaOFA

As a side note, I'm extremely happy I figured out how to get the Rockman/Mega Man-like noise-percussion down. It's been puzzling me for a while and it's a great self-achievement to have finally discovered how to do it.