In Japan, Mega Man is called "Rockman," which effectively makes his weapon the "Rock Buster." However, despite the name, the Blue Bomber very rarely uses it to bust any rocks. However, as you can see in this screenshot, it seems to be very proficient at busting some rather familiar-looking bricks.
Such is one of many scenarios in explodingRabbit's Super Mario Bros. Crossover, a Flash game on Newgrounds which allows you to play through the entirety of the original Super Mario Bros. with not only Mario, but also Mega Man, Metroid's Samus Aran, The Legend of Zelda's Link, Castlevania's Simon Belmont, and Contra's Bill Rizer, who gets a real charge out of being chosen.
The game has become an instant sensation, sweeping the internet in a mere matter of days. This is because, unlike many ROM hacks which merely switch out the sprites of Mario or his enemies for other characters, this version actually manages to maintain the feel of each character (for the most part).
In addition, each character is able to use Mario's power-ups to enhance their own abilities in such a way that is befitting both the Mushroom Kingdom and their own home games. For example, our friend Rock starts off sans helmet and with a regular Buster shot (plus sliding ability). Grab a Super Mushroom, and he powers up with his helmet on, which allows him to charge his shots and to shatter bricks by jumping. Gain a Fire Flower, and Mega Man can charge up with some literal fire power as he dons red and orange garb.
You can give the game a shot over at Newgrounds here. Be warned, though: the site is largely not-safe-for-work, so venture beyond the game at your own peril.
As an aside, those of you who knew of the game might have been wondering what took so long for us to post (thanks to everyone who tipped us off, by the way). Simply put: policy. We typically don't endorse pirates copies of games or straight-up ROM hacks, and unfortunately, by the very inclusion of Mario, this game is probably teetering perilously close to receiving a letter from Nintendo.
Still, it's difficult to ignore the unique feel of running through familiar territory with a new set of legs, to say nothing of how it can make you appreciate the traditional methods. So if you haven't already, give it a try.