Mega Man 2: The Power Fighters, known in Japan as Rockman 2: The Power Fighters (ロックマン2・ザ・パワーファイターズ), is an arcade video game, released in Japan in 1996 as a fighting game in the Mega Man series of games. It is the direct sequel to Mega Man: The Power Battle released the previous year. Both games were ported to home consoles in North America in 2004 as part of the Mega Man Anniversary Collection for PlayStation 2, Xbox, and GameCube and in Japan during the same year as part of two game compilation titled Rockman: Power Battle Fighters (ロックマン パワーバトルファイターズ), also for the PlayStation 2. An adaptation of both games for the Neo Geo Pocket Color, titled Rockman: Battle & Fighters (ロックマン バトル&ファイターズ), was also made.
Like The Power Battle, each character has an epilogue once the player beats the game. However, in The Power Fighters, the epilogues are more detailed and have more to do with past and future Mega Man games, providing vague explanations regarding characters and canon, most notably the Evil Energy incident from Mega Man 8 and how Dr. Wily created Zero from the Mega Man X series.
The gameplay is roughly the same as in Mega Man: The Power Battle, as it keeps the controls, stages and weapon-copying. There are however several new additions. The playable characters are Mega Man, Proto Man, Bass and Duo, with Duo being a new addition to the cast. The four characters feature different attributes and abilities. When playing 2-Player, only one of the players can get the Robot Master's weapon.
As in The Power Battle there are three "stories" to choose from after; finding Dr. Wily, saving Roll, and recovering the stolen parts. All stories have different Robot Masters to fight, and halfway through it the player is given a different power-up. Unlike the previous game, The Power Fighters lets the player choose freely between Robot Master stages, and is given some hints on what the Robot Masters weaknesses are. Each of the characters can perform a special attack, which is executed by releasing a full buster charge while holding the joystick up. Megaman's special move, the "Mega Upper," is simply a jumping uppercut (like the Shoryuken); Protoman's special move, the "Proto Strike," allows him to shoot a massive, short-ranged burst of energy; Bass' special move, the "Crescent Kick," (Which is like the Flash Kick, Another Street Fighter ability), lets him perform a somersaulting kick; Duo's special move, the "Giant Knuckle," is a standing uppercut that flings the enemy upwards (if the attack button is pressed again after the uppercut, Duo will jump up and slam the enemy down to the ground).
As the player damages the Robot Masters, various energy pellets pop out from them. Some of these are just for points, but others will restore health, weapon energy, or both. When the robot master is defeated, a multitude of these pellets are released, as well as a capsule containing the boss's special weapon. During a two-player game, only the player who picks up the capsule will get the special weapon (similar to those seen in Mega Man 8). One of the items that can appear during battle will summon a robot helper. Mega Man summons Rush, who will do a dash attack towards the enemy when Mega Man fires a charged shot, and can be bounced from using the Rush Coil. Bass summons Treble, who will fire plasma shots each time Bass fires his buster, and perform a dash attack similar to Rush's when Bass fires a charged shot. Protoman and Duo both summon Beat, who will give them an energy shield that makes them completely invincible for a short time. These summoning abilities will last until their energy runs out, and they cannot be cancelled. While a helper or their effect is active, special weapons cannot be used. Lastly, each Robot Master now has an Overdrive mode; after a Robot Master loses half or more of their health, the screen will go dark, they will flash, and their attack patterns will change. Some Robot Masters will gain new moves, some will gain new weapons, and others will simply become much harder to hit.
Source: Wikipedia, "Mega Man 2: The Power Fighters", available under the CC-BY-SA License.