Mega Man X4

Mega Man X4, known as Rockman X4 (ロックマンX4) in Japan or shortened by fandom as MMX4, is the fourth game from the Mega Man X series. It was the second game in the series to be released on the Sega Saturn and Sony PlayStation (although it is the first original game; Mega Man X3 was ported to the systems), released in 1997 (and also re-released onto PlayStation as part of its greatest hits in 2002). It was later ported to the PC in 1998 and then re-released as part of the Mega Man X Collection. It was released on the Playstation Network in North America as part of the PSOne classics on September 2, 2014, which was later released in Japan on December 17, 2014.

Plot
The storyline differs slightly depending on whether the player chooses Mega Man X or Zero. Mega Man X4 takes place in an ambiguous year in the 22nd century (21XX), where humans coexist with intelligent androids called "Reploids". Following the third defeat of Sigma, a second Maverick Hunting group has arisen. The army, called the "Repliforce", is a strict military regime led by the giant Reploid General and his second-in-command, Colonel. Some time later, behind the scenes, General has been meeting with a mysterious figure who plots the Hunters' demise, trying to convince General that the Hunters are dangerous, and will turn on him in an instant. General dismisses the figure, unwilling to betray the Humans. Zero, meanwhile, is plagued by a recurring nightmare: a mysterious figure awakens him, calling him a "masterpiece", then orders him to destroy an unknown target before fading away. As Zero tries to stop the figure, he is paralyzed by a horrible pain, which is followed by visions of carnage. Mayhem breaks out, however, when the Sky Lagoon, a massive floating city, is sent crashing down onto the city below it, killing countless humans and Reploids alike. The game begins here where either X or Zero is dispatched to investigate possible causes of the disaster, only to become entangled in a struggle to save the world. At the crash site, X and Zero encounter Colonel, and attempt to bring him back to Maverick Hunter HQ for investigation. Colonel denies Repliforce's involvement in the Sky Lagoon destruction, and refuses to disarm out of pride. Zero also rescues Iris, Colonel's kind-hearted sister, who was caught in the mayhem but is otherwise unharmed, and sends her to headquarters. 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 rendezvous with Iris. Double and Iris outline the locations of eight Reploid leaders who have sworn their loyalty to Repliforce's coup. Once four of the eight Mavericks are defeated, Colonel issues a challenge to X and Zero, which he either escapes from after defeat (X) or is stopped by the intervention of Iris (Zero). 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 then dies after an ensuing battle. The two protagonists then infiltrate the Repliforce's space station, known as the Final Weapon, which is capable of destroying all human life on Earth. X must fight Double, who is revealed to be a double agent to gain information from the Hunters. Zero is reluctantly forced to battle Iris, who is torn between the ideals of her brother and her feelings for Zero. Once Double, Iris, and General are defeated, Sigma reveals himself as the mastermind of creating the conflict between the Maverick Hunters and Repliforce and announces his intention to wipe out humanity. Additionally in Zero's scenario, Sigma reminds Zero of the time that Sigma led the Maverick Hunters, and of a vicious battle between the two that ended with Sigma becoming the Maverick he is today. 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.

The final scene depends on which protagonist was used to complete the game. In X's ending, he thinks back to the battles he had endured: a misunderstanding Colonel, Double's betrayal, and Sigma himself. Zero contacts X and tells him to return to Earth to rest. With his thoughts weighing heavily on him, X begs Zero to promise to take care of him, should he become a Maverick himself. Zero hesitates, then tells X not to have such thoughts. In Zero's ending, he is wrought with pain and guilt for being unable to save any of the Repliforce members, and becomes heartbroken over the death of Iris. He then wonders to himself if all Reploids are destined to become Mavericks after all.

Gameplay
Mega Man X4 follows its predecessors as the player must combat Mavericks while traversing through obstacles and terrain. This is the second game to feature Zero as a selectable playable character, but the first game to feature him as a fully playable character (he had limited playability in the previous game). Unlike future games, players must play the entire game with the character they've chosen.

The playing styles of both characters differ from each other, giving the gamer a rather varied experience. Mega Man X still copies weapons through defeating bosses, utilizing the long range X-Buster. Zero however, learns techniques, which mimics an attack used by a boss, often with the use of his close-ranger Z-Saber, but none of these except his Giga Attack use Weapon Energy. Because of their gameplay differences, X is often recommended for novice to intermediate players since he can fight enemies from a distance while Zero is used for advanced players as he needs to get up and close to his targets.

The game is also the first to have actual multiple Armors in the game, as well as an "Armor" for Zero. X can find pieces for the Fourth Armor like he would any other armor in the previous games, enhancing his abilities further.

Finally, Mega Man X4 is the first X game to use cheat codes which unlock armors specific for the character selected. For X, he unlocks the Ultimate Armor (an enhanced version of the Fourth Armor), which first starts out replacing X's cyan colors with purple. When X visits any of the Light Capsules, he is automatically equipped with the full Ultimate set, giving him a Plasma Shot upgrade and the Nova Strike Giga Attack as well as enhanced defense and the ability to hover in the air (these abilities were also featured in the Fourth Armor, although the latter's use of the Nova Strike is limited). Zero on the other hand gets the Black Zero armor, which gives him a black sheen and platinum blond hair, but does not affect his abilities in the least. The codes for unlocking these armors differ on the consoles.

Bosses
Eight Mavericks:

Others:
 * Eregion
 * Colonel
 * Double (If X), Iris (If Zero)
 * General
 * Sigma

Armors
X's Armors:
 * Standard: X begins the game with his default armor.
 * Fourth Armor: An all-around armor.
 * Ultimate Armor: Obtained by visiting any Light Capsule after the use of a code. Completely-advanced version of Fourth Armor (Nova Strike can be used without recharging energy).

Zero's Armors:
 * Standard: Zero begins the game with his default armor.
 * Black Zero: Changes the color of Zero's armor through the use of a code. Cosmetic change only.

Trivia

 * Like Mega Man 8, X4 has been a target of ridicule due to its sub-par voice-acting, including X being voiced by the same actress who portrayed Mega Man in 8, which received similar criticism. This game was also the first in the series to utilize a dialogue sequence between the Hunters and the Mavericks instead of going straight to the battle. This would carry on for the rest of the series.
 * Similar to Mega Man 8, the game's bosses would give a voiced line of dialogue just before the battle began, as well as reactions to being attacked during the battles Unlike Mega Man 8 however, these were not translated for Mega Man X4's western release, and simply removed from the game with the exception of Magma Dragoon's dialogue during battle.
 * It is not known which ending in this game is canon: X's or Zero's. This stems from the fact that both Zero's battle with Colonel and X's battle with General are referenced by Spiral Pegasus in Mega Man X5, and also images of Zero battling Colonel and X fighting Double in the opening. It is most likely a combination of both endings.
 * Some of the Special Weapons in this game are re-used in the battle between X and Zero (if the player chose Zero) in Mega Man X5. The Special Weapons in question are Soul Body, Double Cyclone and Frost Tower.
 * This is the first game to show official names for an armor; ironically, it is for the secret Ultimate Armor.
 * It should be noted that this is the debut of the Ultimate Armor and Black Zero as unlockables.
 * Although there are two more games in the X series in which the Final Boss is fought in three battles (Mega Man X and Mega Man X8), X4 is the only game where the player fights Sigma in all three phases.
 * X4 is also the only game in which Sigma uses two forms alternately in one battle, which is the case for the final phase of the boss battle.
 * X expresses fear in the ending that he himself may become Maverick. He requests to Zero that, should he ever exhibit symptoms of him becoming a Maverick, that he is to "take care of him".
 * The ending monologue in X's story also seems to implicate foreshadowing that he may become a Maverick in the future as well, hinting his original intended role in the first Mega Man Zero game, which was changed to be Copy X.
 * Chill Penguin and Blizzard Buffalo make cameo appearances in the background of Frost Walrus' stage. Buffalo was killed and frozen by Frost Walrus in Yoshihiro Iwamoto's Rockman X4 manga.
 * This game marks the first time that a "Warning" signal is used when a Boss is about to be fought.
 * On a few occasions, the game may become stuck on a "Warning" signal on the PlayStation version, forcing the player to have to reset the game. This glitch also occurs in Mega Man X5.
 * Unlike Mega Man 8, the Sega Saturn version features no major differences from the PlayStation version. Some of the graphical effects were dithered on the Saturn hardware, such as the searchlights in the first part of the intro stage. Despite the slight downgrades, there are some exclusive enhancements such as seamless track looping, as well as a cresendo at the beginning of the music for the Frost Walrus stage and the intro stage boss. There is also a heat wave effect in the background of the ground portion of the intro stage and Magma Dragoon's domain.
 * On the PC version, the music for the final battle with Sigma was switched around. In other words, the music that played for the first phase of the battle on the Saturn and PlayStation versions became the final phase in the PC version and vice-versa. This can be easily fixed, if one goes into the game's "BGM" folder, and swaps the names of "BGM01.SE" and "BGM02.SE" around. In fact, the game uses regular wave audio files (renamed with a ".SE" extension), so, any music that the player wants to hear can be placed anywhere throughout the game, as long as it's in .wav format, by simply renaming any desired wav files with the appropriate BGMXX.SE title and placing it in the BGM folder, making sure to back up the original files. Mega Man X3 and X5 on the PC works in the same manner.
 * X's eyes appear blue in the anime cutscenes, where canonically they are green. On the flip side, Zero's eyes are green in the cutscenes while they are canonically blue for the most part.
 * Mega Man X4 is the last in the series to have cutscenes animated with hand painted cels and the only in the series to have cutscenes with voice and cel animation.
 * In the 1st Sigma battle during "Round 2", it is possible to stand right behind Sigma as he uses his eye lasers on the floor, allowing a number of free hits until the attack ends. This is easier to attempt as Zero.
 * The crossover game Project X Zone features X and Zero as playable allies. Some of their Special Weapons and techniques are from Mega Man X4, namely Frost Tower and Twin Slasher for X and Kuuenbu, Hyouretsuzan and Raijingeki for Zero. Certain events in Project X Zone suggest that the game's plot occurred some months after the Repliforce incident.
 * In this game, only three of the eight stage bosses are actual virus-infected Mavericks, as their health bars display Sigma's symbol on their bottom instead of the Repliforce emblem. They are Magma Dragoon, Split Mushroom and Cyber Peacock. The other five, as well as the rest of the Repliforce, are just revolting for having been deemed Mavericks.
 * Sub-bosses have their own health bar in this game, with skull symbol under it.
 * The Windows version added an additional easy mode but the only noticeable difference is the player's damage received from enemies being halved in easy mode. This easy mode is only present in Windows version of this game.
 * The Windows version also added an additional music test mode which is not available in other versions.