Mega Man X4, originally released in Japan as Rockman X4 (ãƒãƒƒã‚¯ãƒžãƒ³X4), is an action-platform game developed and published by Capcom. It is the fourth game in the Mega Man X series and the second game in the series to be released on the Sega Saturn and PlayStation. The two versions were released simultaneously in Japan in 1997. A North America release followed sometime thereafter, while Europe received only the PlayStation version in 1997. Mega Man X4 allows the player to choose between the two mechanoid "Reploids" protagonists at the beginning of the game: X, who uses traditional, long-range attacks; or Zero, who wields a short-range sword.
Mega Man X4 takes place in an ambiguous year in the 22nd century (21XX), where humans coexist with intelligent androids called "Reploids". A second Maverick-hunting group has been formed to supplement the Maverick Hunters, though its relationship with the humans is tenuous. The army, called the "Repliforce", is a military regime led by the giant Reploid General and his second-in-command, Colonel.[4] The storyline differs slightly depending on whether the player chooses X or Zero.
In the game's introduction, the Sky Lagoon, a massive floating city, is attacked by a Maverick and sent crashing down onto the city below it, killing countless humans and Reploids.[5] At the crash site, Zero rescues Iris, Colonel's kind-hearted sister, who was caught in the mayhem but is unharmed. X and Zero then encounter Colonel, suspicious of his presence, and attempt to bring him back to Maverick Hunter HQ for questioning. Colonel denies Repliforce's involvement in the Sky Lagoon destruction, and refuses to disarm out of pride.[6] The Repliforce thus begins a movement to claim independence from the human government and create a nation for Reploids only.
Back at headquarters, X is greeted by a rookie Hunter named Double, while Zero rendezvouses with Iris. Eight Mavericks who have sworn allegiance to Repliforce are outlined for X and Zero to eliminate. One of them, ex-Hunter Magma Dragoon, reveals that he caused the Sky Lagoon incident for a chance at fighting X and Zero, but hints that he was working for someone other than Repliforce.[7] Once all eight Mavericks are beaten, X and Zero are sent to a space port where Colonel guards Repliforce's launch into outer space; Colonel dies in the ensuing battle. X and Zero infiltrate the Repliforce's space station, known as the Final Weapon. X must fight Double, who is revealed to be a double agent sent to gain information from the Hunters,[8] while Zero is forced to battle Iris, who is torn between her brother's dream and love for Zero.[9] Zero kills Iris in the confrontation, which causes him to break down in an existential crisis. The genocidal Maverick Sigma then reveals he orchestrated the Sky Lagoon crash and sent Dragoon and Double to instigate the conflict between the Maverick Hunters and Repliforce.[10] Additionally in Zero's scenario, Sigma reminds him of the time that Sigma led the Maverick Hunters, and of Zero's origin as a Maverick that led to vicious battle between the two where the Maverick Virus passed from Zero to Sigma. In the end, Sigma is destroyed, but reveals he already activated the Final Weapon. General then appears and sacrifices himself to destroy the Final Weapon, allowing X and Zero to escape and return to Earth.[11] As they escape, X begs Zero to promise to kill him should he become a Maverick, but he does not answer. Meanwhile, Zero is wrought with pain and guilt for being unable to save any of the Repliforce members, most notably Iris.