SFxMM is a fan-made game cover of Megaman, an old 8-bit platformer that lived on the original Nintendo Entertaiment System since the late '80s/early '90s. The mechanics of the game are simple: run, shoot, jump and slide through each stage until you reach the boss at the end. Though the game is centered around the Blue Bomber himself, most of the fan service seems to be aimed at Street Fighter fans, as the world fighters are transformed into 8-bit sprites. Megaman hasn't fought Ryu since Marvel vs. Capcom 2, nor performed a hadoken since the X series (secret capsule in Armored Armadillo from Megaman X).
In fact, most of the in-game music is chiptune variations that span the Street Fighter series, from II to IV. Robot enemies are inspired by the special moves that characterize each fighter from the SF series, like Soul Strikes and Hadoukens. Bosses will not only throw all their signature techniques, but every boss character becomes stronger as they rack up damage, just like the ultra meter system in Street Fighter IV.
Considering that the many of current fans of Street Fighter fans are from the same generation that grew up with such iconic franchises as Megaman, they'll find a lot to love in this charming rendition.