Mega Man, alternatively written as Megaman and MegaMan, known as Rockman (ロックマン, Rokkuman?) in Japan, is a video game franchise from Capcom, starring the robot character Mega Man, or one of his many counterparts. Mega Man, released for the Nintendo Entertainment System in 1987, began a series of over 50 games on multiple systems. As of December 31, 2010, the series has sold approximately twenty-nine million copies worldwide, making it Capcom's most prolific franchise.

Mega Man 2, known in Japan as Rockman 2: Dr. Wily no Nazo (ロックマン2 Dr.ワイリーの謎?, lit. "Rockman 2: The Mystery of Dr. Wily"), is a platform game developed and published by Capcom for the Nintendo Entertainment System. It is the second installment in the original Mega Man series. The game was released in Japan in 1988, and in North America and PAL regions the following years. Mega Man 2 continues the titular protagonist's battle against the evil Dr. Wily and his rogue robots. The game features graphical and gameplay changes from the first Mega Man game, many of which have remained throughout the series. Although sales for Mega Man were unimpressive, Capcom allowed the Rockman team to create a sequel. They worked concurrently on other Capcom projects, using their free time to develop the game. Unused content from the previous title was integrated into Mega Man 2. Takashi Tateishi composed the soundtrack, with Yoshihiro Sakaguchi serving as a sound programmer. With more than 1.5 million copies sold, the game is the best-selling Mega Man title. Critics praised its audio, visuals and gameplay as an improvement over the first game. Many publications rank Mega Man 2 as the best title in the series, and as one of the greatest video games of all time. The game has been re-released on several consoles and mobile phones.

Mega Man 3, known as Rockman 3 Dr. Wily no Saigo!? (ロックマン3 Dr.ワイリーの最期!?, Rokkuman Surī Dokutā Wairī no Saigo!??, lit. "Rockman 3: The End of Dr. Wily!?") in Japan, is a video game developed and published by Capcom for the Nintendo Entertainment System. It is the third game of the original Mega Man series and was originally released in Japan on September 28, 1990. The game localized in North America later in 1990 and in European regions in 1992. Taking place after the events of Mega Man 2, the plot follows the titular hero as he helps his creator, Dr. Light, and a former villain, Dr. Wily, collect parts for a peace-keeping robot by defeating several Robot Masters that have gone haywire. A platform-action game, Mega Man 3 follows the same format set forth by its two predecessors. The player, as Mega Man, must complete a series of stages in any order. Defeating a stage's boss will earn the player its special weapon, which can be selected and used at will throughout the rest of the game. Mega Man 3 introduces new gameplay elements such as Mega Man's canine sidekick Rush and the ability to slide along the ground. Unlike with the first two installments of the series, artist and designer Keiji Inafune has considered the creation of Mega Man 3 to be very stressful due to time constraints and his own increased responsibilities during its development. Following the success of Mega Man 2 released two years earlier, Mega Man 3 has sold over one million copies and has been positively received in critical reviews. Its presentation and gameplay has been especially praised, although many sources found the game to be too difficult. Like other titles in the series, Mega Man 3 has been re-released several times on other gaming platforms, on mobile phones, and as part of various Mega Man franchise compilations.

Mega Man 4, known in Japan as Rockman 4 Aratanaru Yabō!! (ロックマン4 新たなる野望!!, Rokkuman Fō Aratanaru Yabō!!?, lit. "Rockman 4: A New Ambition!!"), is a platform game developed by Capcom for the Nintendo Entertainment System. It is the fourth game in the original Mega Man series and was originally released in Japan on December 6, 1991. The game was localized in North America the following January, and in Europe in August 1993. The game's story takes place after the third defeat and supposed death of Dr. Wily, and features the Earth coming under threat from a mysterious scientist named Dr. Cossack and his eight "Robot Masters". Fearing the worst, Dr. Light sends Mega Man to save the world once again. Mega Man 4 carries on the same action and platforming gameplay as the first three games, in which the player completes a series of stages in any order and adds the weapon of each stage's boss to Mega Man's arsenal. One notable added feature is the "New Mega Buster" (often shortened to "Mega Buster"), an upgraded arm cannon that lets the player charge a regular shot into a much more powerful blast. The development team was mindful that this innovation would change the overall feel of the game. Despite Mega Man 4 receiving positive critical reviews during its early 1990s release, the game is widely regarded today to represent a downward shift from the quality of the first three games in the series. The Mega Buster itself has been considered an overused mechanic by several sources. Mega Man 4 was re-released on the Japanese PlayStation, PlayStation Network, and mobile phones; the North American Mega Man Anniversary Collection; and worldwide on the Virtual Console for 3 Nintendo systems (Wii, Nintendo 3DS and Wii U).

Mega Man 5, known as Rockman 5 Blues no Wana!? (ロックマン5 ブルースの罠!?, Rokkuman Faibu Burūsu no Wana!??, lit. "Rockman 5 Blues' Trap!?") in Japan, is a video game developed by Capcom for the Nintendo Entertainment System. It is the fifth game in the original Mega Man series and was originally released in Japan on December 4, 1992. It saw a release during the same month in North America and in 1993 in Europe. The plot takes place after the fourth defeat of the evil Dr. Wily at the hands of the heroic robot Mega Man in the year 20XX. Mega Man's brother and ally Proto Man uncharacteristically leads a group of menacing robots in attacks on the world and kidnaps his own creator Dr. Light, leaving Mega Man little choice but to take up arms in a fight against his once trusted sibling. Mega Man 5 carries over the same graphical style and action-platforming gameplay as the four preceding chapters in the series. The game introduces a new character, Beat, whom the player can use as a weapon once a series of eight collectable letters are found. Mega Man 5 was met with an average to fairly positive critical reception, with the one major complaint being its lack of originality in either its plot or gameplay. Like other NES games in the series, Mega Man 5 has been re-released in Japan on the PlayStation, PlayStation Network, and mobile phones; in North America as part of the Mega Man Anniversary Collection; and in both regions on the Wii Virtual Console. It has been released in North America, Europe, and Japan on the 3DS Virtual Console.

Mega Man 6, known in Japan as Rockman 6 Shijō Saidai no Tatakai!! (ロックマン6 史上最大の戦い!!, Rokkuman Shikkusu Shijō Saidai no Tatakai!!?, lit. "Rockman 6: The Greatest Battle Ever!!"), is a video game developed by Capcom for the Nintendo Entertainment System (NES). It is the sixth installment in the original Mega Man series and was originally released in Japan on October 5, 1993 and in North America the following March. It was included in the Mega Man Anniversary Collection released in 2004. Its first PAL region release was June 11, 2013 for the 3DS Virtual Console, nearly twenty years after the game's first release. The story of Mega Man 6 opens during a competitive robot fighting tournament with entrants from all around the globe. A villainous figure known as "Mr. X" announces he has reprogrammed the eight powerful contestants with intent to use them for taking over the world. The game's robotic protagonist Mega Man, who was sent to oversee the tournament, springs into action to foil X's plot. A standard action-platformer, Mega Man 6 plays nearly identically to its five predecessors with a few added features such as stages with alternate pathways and new Rush adaptors. Mega Man 6 is the first game in the series to receive character design input from fans outside of Japan. This late-era game was also the last in the series released on Nintendo's 8-bit console. Due to the declining support of the NES and the growing presence of the newer and more powerful Super Nintendo Entertainment System (SNES), Capcom decided not to publish Mega Man 6 in North America. The North American version of Mega Man 6 was released by Nintendo of America instead. Critical reviews favored the game's comparable presentation and use of the established gameplay model from preceding chapters in the series, though nearly all judged it a redundant sequel. While the first five Mega Man games are available on the Wii's Virtual Console, this game is absent from the Wii Shop Channel; however the game was released via the 3DS Virtual Console in Japan and Europe, with North America on June 20, 2013.