I can't decide if this guy sounds like Eddie Vedder, Adam Sandler, or the Bud Light "Real Men of Genius" singer. But he's singing, "MEGA MEGA MEGA MANNNN ... HE'LL SAVE THE EFFIN' DAY."
Brentalfloss put this up on YouTube yesterday. It's kind of a schtick with him (see Mega Man 3, 6, first Dr. Wily level of Mega Man 2, all more than two months old ) But this title has a special place in the hearts of many, so sit back and enjoy.
This probably is also a good place to mention that, over on Capcom Unity, they're teasing the Mega Man 9 soundtrack as available soon through the Capcom store. (See left:)
I'm gonna have this shit stuck in my head all day. Megamegamega Mannnnnn ... now backwards you would say: Man Mega!"
Mega Man 2 Title with Lyrics [YouTube via GoNintendo]