Super Smash Bros. for Nintendo 3DS / Wii U

Super Smash Bros. for Nintendo 3DS and Wii U, known in Japan as Dairantō Sumasshu Burazāzu fō Nintendo Surī Dī Esu / Wī Yu, are two video games released for the Nintendo 3DS and Wii U. They are officially considered the fourth and fifth installments in the Super Smash Bros. series of fighting games, which features several Nintendo characters.

During E3 on June 12 2018, it was confirmed these games would be succeeded with Super Smash Bros. Ultimate on the Nintendo Switch.

Development
The game was first announced at E3 2011, but no further information was released due to Masahiro Sakurai working on finishing Kid Icarus: Uprising. At the start of 2012, the game was officially in production, but new information was not released until the following year.

On June 11, 2013, two trailers were shown during a Nintendo Direct: one announcing the game and the Villager from Animal Crossing as a newcomer, and another announcing that Mega Man would also be a playable character.

One more trailer was released before the end of E3 2013 showing that Wii Fit Trainer would be playable for the first time. Afterwards, the game's official site started revealing at least one playable character per month, and other content like stages and items.

Mega Man
The original Mega Man appears as a playable character. Other Mega Man related appearances in the game include Rush (who uses Rush Coil), as well as Mega Man wielding several Special Weapons. The Wily Castle from Mega Man 2 appears as a stage, and the Yellow Devil appears on it as a stage hazard.

It is one of the few stages to be on both versions, but with some minor differences. Elec Man appears as an Assist Trophy character, and the Met as an enemy in the Smash Run mode from the 3DS version. Mega Man also has an amiibo figure, and Proto Man, X, MegaMan.EXE, and Zero appear as DLC costumes for the Mii Fighters.

Mega Man's moves

 * Neutral attack/Neutral aerial attack/Forward tilt: Mega Buster
 * Up tilt: Mega Upper
 * Down tilt: Sliding
 * Dash attack: Top Spin
 * Side smash attack: Charge Shot
 * Up smash attack: Spark Shock
 * Down smash attack: Flame Blast
 * Forward aerial attack: Flame Sword
 * Backwards aerial attack: Slash Claw
 * Up aerial attack: Air Shooter
 * Down aerial attack: Hard Knuckle
 * Grab: Super Arm
 * Neutral special attack: Metal Blade (Hyper Bomb and Shadow Blade)
 * Side special attack: Crash Bomber (Ice Slasher and Danger Wrap)
 * Down special attack: Leaf Shield (Plant Barrier and Skull Barrier)
 * Up special attack: Rush Coil (Beat and Tornado Hold)
 * Final Smash: Mega Legends: Mega Man fires a Black Hole Bomb that sucks opponents in. Inside the resulting vortex, MegaMan.EXE, Mega Man X, Mega Man Volnutt, and the Star Force Mega Man appear alongside Mega Man before charging their busters to fire off a powerful Shining Laser-like beam from each simultaneously, doing major damage to the opponents who were sucked into the initial vortex.

Mega Man's alternate colors

 * Mega Buster (dark blue and blue)
 * Rush Coil (red and white with red joints)
 * Leaf Shield (green and white with yellow joints)
 * Metal Blade (dark yellow and yellow with green joints)
 * Air Shooter (light blue and white)
 * Slash Claw (green and yellow)
 * Flame Sword (red and yellow)
 * Top Spin (dark gray and yellow)

Assist Trophies
Assist Trophies are items that, when picked up, will break and summon a random character from the Trophy. Elec Man is one of the characters that appears as an Assist Trophy, attacking opponents with his Thunder Beam.

Both versions
The Trophies shown are from both versions.

Note: Dr. Wily's pose is different between both versions.

Version differences

 * Some text differs between the Japanese and English versions of the Mega Man trailer to reflect localization differences, such as:
 * Clash Man/Clash Bomb becoming Crash Man/Crash Bomber.
 * Guts Man's serial number DRN 004 becoming DLN 004.

References to the Mega Man franchise

 * The silhouettes of the Robot Masters in the trailer introducing Mega Man are from their original official artwork.
 * It has been noted that when Mega Man uses attacks that require both arms, he vents them afterwards. This is a nod to Super Adventure Rockman where he uses both Mega Busters to finish off Ra Moon while being warned by Dr. Wily that he could overheat himself while doing so.
 * The above artwork done by Ryuji Higurashi was done in the same style that was used for the original Mega Man series Japanese box arts, with eight characters representing stage bosses and Bowser being the main villain.

Marketing tie in

 * The variant covers of Archie Comics' Sonic Universe #69, Mega Man #42, and Sonic the Hedgehog #266 depicts Shadow, Mega Man, and Sonic in a Super Smash Bros.-like cover.

Mega Man's additional encounters with other Smash Bros characters

 * Following the Archie Comics' storyline Worlds Collide, this game marks the first encounter of Mega Man and Sonic the Hedgehog in a video game.
 * Ryu from Street Fighter appeared with Sonic and Mega Man in Worlds Unite, and has made several appearances alongside Mega Man in past video games such as Marvel vs. Capcom: Clash of Super Heroes and Street Fighter X Mega Man.
 * This marks the first time that Mega Man encounters Donkey Kong, Link, Zelda and Pit in a video game since they appeared in Captain N: The Game Master.
 * Incidentally, this will feature the first encounter between Mega Man and Samus Aran who have both appeared in Captain N, though the former appeared only in the cartoon, while the latter was only in the comic.
 * Before Super Smash Bros., Mega Man appeared in the German Club Nintendo comics Super Mario: Die Bescherung and Super Mario: Die Verwandlung. Therefore this will be the first meeting of Mega Man with Mario, Luigi, Peach, and Yoshi in a video game.
 * Additionally, Captain N: The Game Master had music and sound effects from the Super Mario Bros. game. Season 2 and 3 also premiered in the same hour/half-hour as The New Adventures of Super Mario Bros. 3 and Super Mario World on Saturday mornings.
 * This is the second time that Mega Man and Pac-Man appear in a fighting game together, the first being the PS3 version of Street Fighter X Tekken, although Mega Man's appearance was based on Bad Box Art Mega Man.
 * Mega Man's 8-bit sprite can be seen on Pac-Man's promotional picture.

Trivia

 * Mega Man's Final Smash is similar to both the Pokémon Trainer's Triple Finish from Super Smash Bros. Brawl, and Palutena's Black Hole Laser from Super Smash Bros. for Nintendo 3DS and Wii U.
 * Ryu from Street Fighter is the second third party playable character in the game to originate from Capcom, the first being Mega Man as well as the first third party character to be a downloadable character.
 * Mega Man's Boxing Ring title is "Blue Metal Hero" in the American version and "The Blue Bomber" in the European version.