RockMan Battle & Fighters

Rockman: Battle & Fighters is a portable, stripped-down compilation of two arcade fighting games:

Mega Man: The Power Battle
Mega Man 2: The Power Fighters

The game has robots-heroes from the Mega Man (Rockman) series: Mega Man, Proto Man, Bass (the second game has a fourth character, Duo). The player controls one of them and must fight against another robots (bosses from the Mega Man series).