Street Fighter X Mega Man

Street Fighter X Mega Man is a platform game in the series. It was developed by Seow Zong Hui and published by Capcom and released on their website for free for the 25th anniversary of Mega Man (since the release of the first game in 1987) on December 17, 2012. The game features traditional gameplay with characters as robot masters.

"Having fought countless robot masters over the years, Mega Man is ready to lay back, relax and enjoy his 25th Anniversary. Getting wind of this, Ryu and his fellow Street Fighters want one last battle before they let their own anniversary finish. Charge up your mega busters and stretch out your lightning legs, this is Street Fighter® X Mega Man®!
 * Official description

A true collaboration between Capcom and its fans for Mega Man's and Street Fighter's 25th Anniversary, Street Fighter® x Mega Man® was created and developed by Singapore native Seow Zong Hui (aka "Sonic"), with an original soundtrack by Luke Esquivel (aka "A_Rival") and with support provided by Capcom. Street Fighter® X Mega Man® stars the Blue Bomber as he goes toe-to-toe with some of Street Fighter's most beloved characters complete with their own individual themed stages and boss battles. Jump, shoot, and use your special new Street Fighter abilities to defeat your foes and become the world's strongest robot!"