You are Mega-Man, Dr. Wily has sent 8 machines after you. You defeat each every one of them except 1, Snake Woman. You get to the place Snake Woman was, and get to running and jumping on many platforms and attacking as many enemies as you can. You eventually reach a steel door and open the door to see Snake woman, with a few of her Search-Snakes on her.

S-W: "Ssssurprise, Mega-Man! You won't have a 2nd chance after this battle."