The Mega Man franchise (known as Rockman in Japan) is a long-running saga of video games created by Capcom. The games revolve around robotic heroes whose exploits take them into conflict with other robots and those who would use robotics to bring destruction and chaos to the world. Most of the games follow the same platforming style of running and shooting enemies, with common themes and quirks such as respawning enemies, choosing which order to clear levels and gaining power-ups from each defeated boss. There have been seven different Mega Man game series, each taking elements from the others as well as introducing new content and concepts.
Mega Man Game Series
Mega Man Classic
The series that started it all. The original Mega Man series - set in the era 20XX - revolved around the adventures of Mega Man, a robot upgraded from being a household labourer into a combat robot. Mega Man battles the endless robot forces of the mad scientist Dr. Albert Wily, who wants to prove his genius by taking over the world and building a robot-dominated society. The Mega Man Classic series introduced such gameplay mechanics as respawning enemies when the player goes back to a spot in the stage where enemies previously appeared. Also, a key feature in the Classic series and just about all the others succeeding it is acquiring new weapons and powers from bosses that have been defeated.
Mega Man X
Set in 21XX, the Mega Man X series sees the advancement of robots into truely sentient beings following the discovery of Mega Man X, successor of the original Mega Man and the last of Dr. Light's creations. The main focus of the new series is a seemingly endless conflict against Mavericks, robots who rebel against society and seek to harm humans. Almost no human characters appear throughout the X series, the story revolving around the Reploids and their continued advancement. New gameplay aspects include the main characters' ability to dash and wall-climb, which the old Mega Man could not do. There is also the introduction of pilotable vehicles and mechs, armour upgrades and new weapons that can be charged up much like the classic Buster weapon.
Mega Man Legends
Mega Man Zero
The Zero series continues on from the X series. In the 22XX period, Zero - former Maverick Hunter and partner of X - has awoken from a decades-long sleep into a ruined world where Reploids are being oppressed by the human society of Neo Arcadia. Though he does not recall much of his past, Zero is willing to stand with the resisting Reploids who are struggling to survive. Zero's combat skills from the X series are mostly retained, though he now possesses the projectile skills of Mega Man X as well. Boss abilities are more limited in this series and Zero can only enhance his weaponry with three element chips: electric, fire and ice. He can also pick up new weapons and modifications by collecting disks in each of the stages he travels to.
Megaman Battle Network
Megaman Star Force
Mega Man ZX
Progressing further into the future of the mainstream Mega Man timeline, the 23XX era has seen the unison of humans and Reploids, where Reploids have given up their immortal robot bodies in favour of living flesh and blood, fully intermingling with their human makers. During this period, sentient devices known as Biometals have been discovered and villainous forces are at work to abuse their power. In the ZX series, players have the choice between a male or female character who may have different names but the same identity and follow the same story. The element-based weapon upgrade system from Mega Man Zero is enhanced upon with the acquisition of new Biometals that change the player character's form and powers.