[[quoteright:270:http://static.tvtropes.org/pmwiki/pub/images/270px-mmx4promo_7840.jpg]]

''Mega Man X4'' is the fourth entry in the ''VideoGame/MegaManX'' series, released on the UsefulNotes/PlayStation and UsefulNotes/SegaSaturn on August 1997 in Japan, September 1997 in North America, and October 1997 in Europe. It was also the first ''Mega Man X'' game not to be released on the UsefulNotes/SuperNintendoEntertainmentSystem.

[[ExtyYearsFromNow In the year 21XX]], two major Reploid organizations exist to counter Maverick activity -- the Maverick Hunters including X and Zero, and the new group, Repliforce. Some time before the game, Zero got to know Iris, the sister of the Repliforce Colonel. One day, the aerial Sky Lagoon is suddenly attacked, causing it to crash to the ground. As Repliforce was in the area, they're suspected to be responsible and the Colonel is asked to disarm his men and come in for questioning; however, he refuses due to his pride. To make matters worse, the Repliforce General launches a coup d'état to start a nation only for Reploids, which immediately causes the entirety of Repliforce to be labeled as Mavericks, forcing the Maverick Hunters to turn against their allies.

Maverick bosses:
* Web Spider of Repliforce, gives [[FloatingPlatforms Lightning Web]] to X, and [[ShockAndAwe Raijingeki]] to Zero; is weak to Twin Slasher / Shippuuga.
* Split Mushroom, gives [[SelfDuplication Soul Body]] to X, and [[SpinAttack Kuuenzan]] (as well as [[DoubleJump Kuuenbu]]) to Zero; is weak to Lightning Web / Raijingeki.
* Cyber Peacock, gives [[PlayerGuidedMissile Aiming]] [[FrickinLaserBeams Laser]] to X, and [[SmartBomb Raku]][[GroundPunch houha]] to Zero; is weak to Soul Body / Ryuenjin.
* Storm Owl of Repliforce, gives [[RazorWind Double Cyclone]] to X, and [[ParryingBullets Tenkuuha]] to Zero; is weak to Aiming Laser / Rakuhouha.
* Magma Dragoon of the 14th Special Unit, gives [[PlayingWithFire Rising Fire]] to X, and [[FlamingSword Ryuen]][[{{Shoryuken}} jin]] to Zero; is weak to Double Cyclone / Raijingeki.
* Frost Walrus of Repliforce, gives [[ElementalBarrier Frost Tower]] to X, and [[AnIcePerson Hyou]][[SwordPlant retsuzan]] to Zero; is weak to Rising Fire / Ryuenjin.
* Jet Stingray of Repliforce, gives [[AttackDrone Ground Hunter]] to X, and [[VideoGameDashing Hienkyaku]] to Zero; is weak to Frost Tower / Hyouretsuzan.
* Slash Beast of Repliforce, gives [[SpreadShot Twin Slasher]] to X, and [[DeadlyLunge Shippuuga]] to Zero; is weak to Ground Hunter / Raijingeki.
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!!Tropes:
* AllThereInTheManual: Did you know that Colonel and Iris were designed to be one perfect Reploid by scientists working for Repliforce? And that said Reploid was supposed to be based on X? The irreconcilable personalities meant the project needed to be [[SplitAtBirth split]] to allow any sort of functionality, with Colonel gaining X's fighting spirit and sense of justice, whereas Iris retained X's compassion and pacifism. This is also evident in their relationship to Zero, as respectively, Colonel is TheRival whereas Iris acts as a [[TrueCompanions True Companion]] to Zero. This is also what causes Colonel to decide to go to war instead of disarming himself and the Repliforce; he literally can't opt for a peaceful solution.
* AscendedExtra: Zero was technically PromotedToPlayable in ''VideoGame/MegaManX3'', but this game allows him to be chosen as the main playable character from the start, and gives a lot of CharacterDevelopment. Unlike X, he gains three cutscenes involving him, as well as appearing alongside X's ending where X worries about being a Maverick and [[spoiler:Double's betrayal.]]
* BackFromTheDead: Despite seemingly being destroyed for good at the end of ''X3'' by Dr. Doppler's antivirus, Sigma somehow managed to survive it. His appearance in a Grim Reaper garb is quite appropriate for his comeback.
* BilingualBonus: All of Zero's sword techniques retain their original Japanese names; for instance, Raijingeki translates to "Thunder God Attack" and Ryuenjin means "Dragon Flame Blade".
* BittersweetEnding: While X's ending is only somewhat bittersweet, Zero's ending really qualifies for this. [[spoiler:Sigma is once again defeated and the Final Weapon is destroyed along with him, but the Repliforce fiasco has taken untold lives, not just the presumed thousands in the Sky Lagoon crash and the subsequent conflict, but including all of the newly introduced major characters such as Iris, Colonel and General (the former two being killed by Zero, the latter performing a HeroicSacrifice to destroy Final Weapon). Also, Zero tragically rediscovers his former Maverick history, unwittingly the source of the Sigma Virus. Even after he saves the day, he even believes he has the possibility of going Maverick again. Whereas [[VideoGame/MegaManX1 the first]] [[VideoGame/MegaManX2 two games]] ended on a triumphant note and [[VideoGame/MegaManX3 the third game]] on a mildly bittersweet note, this game really ended in a much more melancholy way.]]
** It also retroactively turns the ending of ''X3'' into a DownerEnding; [[spoiler:we find out in this game that despite his efforts, Dr. Doppler's antivirus is useless against the Sigma Virus in the long run, the latter finding a way to overcome it, and that Sigma didn't even ''need'' to infect others to incite a war, but instead pull strings and turn the Reploids against each other. Doppler's potential HeroicSacrifice was all for nothing.]]
* BladeLock: Zero and Colonel are engaged in this in Zero's custcene fight against him.
* BloodKnight: Magma Dragoon sabotages Sky Lagoon, ending untold lives just to force X or Zero to have to fight him in a final duel to the death. Frost Walrus is similar, with him being a SociopathicSoldier (he was already wanted by Maverick Hunters before he joined the Repliforce) who thinks that rioting around is a military man's duty.
* BossArenaUrgency: The mini-boss of Split Mushroom's stage is fought over platforms above SpikesOfDoom where the boss flies beneath those platforms and then jumps up to attack you, crushing part of the platform in the process; [[IncreasinglyLethalEnemy if you don't defeat it quickly]], you'll end up with less and less moving room.
* BossSubtitles: After choosing which stage to enter, it begins with a single paragraph explaining what the Maverick did, along with the Maverick's name and sprite. Also, a TitleScream of the boss's name.
* BossWarningSiren: This game introduced them to the series.
* TheCameo: [[VideoGame/MegaManX1 Chill Penguin]] and [[VideoGame/MegaManX3 Blizzard Buffalo]] can be seen frozen in the background of the Snow Base.
* CatapultNightmare: Zero, in his opening cutscene.
* CharacterDevelopment: Zero gets a lot of development in this game, something that would continue in the next games.
* ColonyDrop: Sky Lagoon during the intro stage.
* CoolAirship: Many of them can be seen in the background of Storm Owl and the Space Port stages; they're apparently hammerhead shark-shaped airships.
* CoresAndTurretsBoss:
** The mini-boss of Storm Owl's stage is a periodically opening-and-closing core on the wall which summons multiple WaveMotionGun-shooting drones to distract you.
** [[spoiler:Iris's boss battle is like this; she can only be damaged by attacking its outer crystal core, while her Ride Armor-like body acts as the "turret" that also summons floating mines if you attack it.]]
* CouldHaveAvoidedThisPlot: All of the events past the fall of Sky Lagoon could have been prevented had Colonel simply cooperated with the Maverick Hunters instead of [[HonorBeforeReason letting his pride get in the way]].
* CutsceneBoss: Colonel's Memorial Hall battle in Zero's story. In X's game, it is a BossOnlyLevel, but in Zero's version, it all takes place in FullMotionVideo, culminating with Iris interrupting and reminding her brother that Zero saved her.
* DarkerAndEdgier: For the first time, the Maverick label is used on a group not genuinely having flawed programming (except perhaps for Colonel, that is)[[note]]The third game all but retcons the first and second games' rebellions as being virus-induced[[/note]] (whether by itself or due to Maverick Virus), but merely rebellious (albeit on an army-scale) and Zero's ties to Dr. Wily are revealed, not to mention [[spoiler:Iris' death, which would continue to haunt Zero after the game.]]
* DesignatedLoveInterest: Iris to Zero; they got together sometime between ''VideoGame/MegaManX3'' and this game, and don't share much romantic screentime in the game proper [[spoiler:before Iris's death]].
* DiedInYourArmsTonight: [[spoiler:Iris dies in Zero's arms]].
* DoubleAgent: [[spoiler:[[MeaningfulName Double.]] He even says "Mavericks" (the side he supposedly belongs to) as among the "idiots, all of them", implying that he may be working for yet another party or purely for himself.]]
* DraconicHumanoid: Magma Dragoon.
* DreamIntro: Zero's storyline starts with him having [[NightmareSequence a nightmare]] of a mysterious figure telling him to destroy the world, as well as [[FlashbackNightmare his past, involving lovely shots of]] [[BodyHorror mutilated Reploids by his own hands]].
* DualBoss: Sigma's third phase has 2 forms, one is a robotic gunner with his face on top, and another is his giant disembodied head that lies on the ground. They have separate health bars, as well.
* EasyLevelsHardBosses: When playing as Zero. The Z-Saber's precision and his multiple movement options make him great in the main stages, but since he gains new ''moves'' rather than new weapons, he can't always exploit the bosses' weaknesses. He has no animation-interrupting move against Slash Beast and Magma Dragoon, for instance.
* EnergyBall: The Plasma Buster upgrade, introduced for the Fourth Armor, will make X's charged shot fire a piercing large ball of energy that leaves multi-hitting energy balls in its wake. It's also used for the Ultimate Armor, not just for this game but also in its subsequent appearances.
* EvilLaugh: Sigma in his [[VillainOpeningScene introductory scene]] with the General after the General dismisses him, but not before Sigma assures that the General would soon change his mind about the Maverick Hunters. And he laughs again when he realizes that the General has taken action against the Maverick Hunters in his speech to Repliforce.
** Also, [[spoiler:[[TheMole Double]]]] laughs after he reveals his true form and slaughters some Reploids at Hunter Base, vowing to target X. He also does the laugh before his boss fight.
* {{Expy}}: Magma Dragoon is pretty much [[Franchise/StreetFighter Akuma]] as a dragon Reploid.
* EyeBeams: Sigma in the second phase can attack with this.
* FaceHeelTurn: Magma Dragoon, who betrayed the Maverick Hunters.
** Once accused of turning Maverick, Repliforce starts a coup d'état to create a separate nation only for Reploids.
** [[spoiler:Iris turns on Zero after Zero kills her brother]].
* {{Fauxshadow}}: Happened unintentionally. X, in his ending, tells Zero to retire him if he ever goes Maverick. This is supposed to come to pass in ''Videogame/MegaManZero'' as the original BigBad is the real X who loses his compassion due to countless wars and becomes a KnightTemplar and Zero has to stop him, instead of the copy of X (what ends up happening).
* FireIceLightning: Magma Dragoon, Frost Walrus, and Web Spider respectively.
* FeatheredFiend: Cyber Peacock and Storm Owl.
* FlyingSeafoodSpecial: Jet Stingray, as well as the Kill Fisher enemies in the Jungle.
* FlunkyBoss: Web Spider and Jet Stingray can shoot out spider and stingray drones respectively. Meanwhile, Split Mushroom can [[SelfDuplication deploy multicolored clones of himself, as well as creating a real body double.]]
* GetOut: A calmer example; in the opening cutscene, Sigma attempts to sway the opinion of General into turning against the Maverick Hunters, under the pretense that they're far too eager to please humans and hunt down reploids. General coldly turns down his offer and orders him to leave his presence. Sigma is unfazed though, and accurately concludes that he'll change his mind later before he departs.
* GiantSpider: Web Spider.
* TheGrimReaper: Sigma disguises himself in a Grim Reaper motif, complete with BlackCloak, [[TheFaceless shadowed face]], and a [[SinisterScythe Sinister]] [[LaserBlade Laser Scythe]].
* HardLevelsEasyBosses: When playing as X. As usual, you can rip through bosses like nothing if you know their weaknesses, many of which [[AIBreaker interrupt the boss's attacks,]] and even weaken them beyond damage dealt. He also doesn't have to get too close to the bosses (except for using Rising Fire against Frost Walrus). He has to struggle in the levels, however, because he's not as agile as Zero and can (mostly) only attack things in front of him.
* HeroicBSOD: [[spoiler:Iris' death]] triggers one for Zero, one that lasts all the way until ''VideoGame/MegaManZero 4''.
* HeroicSacrifice: [[spoiler:General ends up sacrificing himself to stop the KillSat Sigma had commandeered to KillAllHumans]].
* [[HijackedByGanon Hijacked By Sigma]]: The games cutscenes make it clear right off the bat that Sigma is alive and is going to be the real villain of the game, but X and Zero don't find that out until they fight him at Final Weapon. Split Mushroom [[LampshadeHanging lampshades]] this if you're playing as X; the Sigma logo also appears in his health bar (Magma Dragoon and Cyber Peacock have it too) instead of the Repliforce logo.
* HonorBeforeReason: After the Sky Lagoon incident, Colonel refuses to disarm his troops to come in for questioning out of pride, which, [[AllThereInTheManual combined with their lackluster performance on the field]], which makes Repliforce as a whole look suspicious. Justified, however, in that (as the manual has stated) he was built without the supposed capability of compassion and pacifism that he was supposed to have, thus he lacked the capability of peaceful reasoning.
** Several Repliforce members, including Storm Owl and Jet Stingray, start attacking innocent civilians in order to drive attention to themselves and away from Repliforce as they prepared to launch into space. This, of course, simply justifies the mandate that Repliforce has turned Maverick and must be destroyed.
* HumongousMecha: Eregion is as tall as the screen. Frost Walrus is possibly the largest "eight stage bosses" character in all of Mega Man ([[VideoGame/MegaManX6 Rainy Turtloid]] comes second), as he stands at 3/4 of the screen height, even larger than [[VideoGame/MegaMan8 Frost Man]]. General is even taller.
* InfinityPlusOneSword: the Ultimate Armor, introduced in this game. It has similar capabilities to the Fourth Armor, including [[BottomlessMagazines unlimited use of uncharged special weapons]], but its Giga Attack can be used repeatedly without requiring him to fill its energy. It can only be acquired with a cheat code, then getting to a Light Capsule to retrieve it.
* InstantAwesomeJustAddDragons: [[WarmupBoss Eregion]] and Magma Dragoon.
* KillEmAll: [[spoiler:Every character in ''X4'' except X and Zero are dead by the end of the game]].
* KillSat: Repliforce's space station, Final Weapon, [[spoiler:with which Sigma plans to use its laser cannon to destroy all life back on Earth]].
* KingOfBeasts: Slash Beast is a lion Reploid, and he certainly acts the part.
* LandSeaSky: Slash Beast, Jet Stingray and Storm Owl represent the army, navy and air force of Repliforce, respectively.
* LaserBlade: Zero now exclusively use the Z-Saber as part of the SuperheroSpeciation. Colonel also uses one.
* LightningBruiser: Slash Beast is quite strong and hardy, and fast enough to [[RacingTheTrain outrun a moving train]]. Magma Dragoon as well.
* TheMole: [[spoiler:Double]].
* MonstrosityEqualsWeakness: Eregion is the second-largest boss in the game and is [[WarmupBoss also the most pathetic]].
* MushroomMan: Split Mushroom.
* NaiveNewcomer: Double is a rookie Maverick Hunter newcomer who likes to assist X, [[spoiler:[[ObfuscatingStupidity or so it]] [[TheMole would seem]]]].
* NearVillainVictory: [[spoiler:Sigma has turned the Repliforce against humanity and caused countless loss of life on both sides, and his string pulling results in Colonel and Iris getting killed by Zero and nearly destroying General, and Final Weapon is mere seconds away from accomplishing its goal by the time X or Zero mop the floor with him. If General hadn't been functional enough to perform a HeroicSacrifice by [[TakingYouWithMe destroying the Final Weapon along with himself]], Sigma's plan would have actually succeeded.]]
* NiceHat: Many Repliforce officers wear one, like Colonel, General, Web Spider, Jet Stingray, and Storm Owl.
* NotHelpingYourCase: Even when it turns out that Repliforce didn't do anything to the Sky Lagoon at all, they don't do much to cover themselves either - see HonorBeforeReason for why.
* ObfuscatingStupidity: [[spoiler:Double seems gullible and clumsy, but he's actually a competent mole and a dangerous fighter]].
* OminousOwl: Storm Owl.
* [[PeacockGirl Peacock Guy]]: Cyber Peacock. Even though he's not female, he acts a little campy.
* PowerupMount: This game introduces 2 [[MiniMecha Ride Armors]]: Raiden attacks with a chargeable LaserBlade [[BladeBelowTheShoulder Below The Shoulder]] and can be used to crush some train cars in Slash Beast's stage and be brought into Magma Dragoon's boss battle. And Eagle is a flying variant with a chargeable ArmCannon, available in Storm Owl's stage. There's also the Ride Chaser high speed bike section in Jet Stingray's stage; you use it to chase him.
* PreAssKickingOneLiner: Most bosses do this.
* [[PromotedToPlayable Promoted To Fully Playable]]: Zero.
* RememberTheNewGuy: Repliforce. We're made to understand they've been around for awhile and have worked with the Maverick Hunters on several occasions. Based on the memo [[AllThereInTheManual in the manual]], they had been established after the third game.
* SadBattleMusic: The [[spoiler:Zero vs Iris]] theme pretty much points out that it's a tragic battle. To a lesser extent, the vs Colonel and General theme; while suitably epic, it also has the vibes of a battle that shouldn't happen from the start.
* SayMyName:
--> '''Zero''': [[spoiler:Iris?! Iris! Iris! Iris... [[TheScream AAAAAAAHHHHHHH!!!!!]]]]
* SchrodingersPlayerCharacter: There are two storylines, one for X and one for Zero. When you choose one, the other won't appear, except in one case: In X's ending, Zero contacts him.
* ShoutOut: Magma Dragoon is a big one to Akuma of the ''Franchise/StreetFighter'' franchise. He even uses the {{Shoryuken}} and the [[KamehameHadoken Hadoken]] by name.
** When he does the Twin Slasher, Slash Beast does a somersault akin to Guile's Flash Kick.
* {{Shotoclone}}: Magma Dragoon.
* SinisterScythe: [[BigBad Sigma]] uses a [[LaserBlade Laser Scythe]].
* SkywardScream: "WHAT AM I FIGHTING FOOOOOOOOOOOOR?!"
* TeleportSpam: Cyber Peacock and Colonel.
* TrailersAlwaysSpoil: [[https://www.youtube.com/watch?v=hyFeS-9zOiA The Japanese commercial]] for this game shows the infamous scene where [[spoiler:Zero yells "WHAT AM I FIGHTING FOR?!" while [[CradlingYourKill cradling Iris's corpse.]]]]
* TurnCoat: Web Spider was once part of the 0th Unit in the Maverick Hunters before transferring himself to Repliforce some time before this game.
* UtilityWeapon:
** [[ShockAndAwe Lighting Web]] can be used to make an [[ImprovisedPlatform improvised wall]] for X to WallJump off of.
** [[PlayingWithFire Rising Fire and Ryuenjin]] can burn wooden logs or ice blocks.
** A [[ChargedAttack fully charged]] Twin Slasher, or Shippuuga, can be used to break away heavy stone blocks.
* VideogameSettings
** {{Cyberspace}}: Cyber Peacock's stage.
** JungleJapes: Web Spider's stage.
** LethalLavaLand: Magma Dragoon's stage.
** LevelsTakeFlight: Storm Owl's stage.
** LocomotiveLevel: Slash Beast's stage.
** MadScientistLaboratory: Split Mushroom's stage is an abandoned lab full of biological horrors.
** SlippySlideyIceWorld: Frost Walrus' stage.
* WarmupBoss: Eregion, the bipedal dragon Mechaniloid of the Sky Lagoon stage.
* WhenAllYouHaveIsAHammer: Zero only has his [[LaserBlade Z-Saber]], so most of his upgrades give him more powerful or versatile sword techniques.
* WilyWalrus: Frost Walrus is a gigantic walrus with ice powers who looks down on the small and weak and acts like a roughneck.
* XanatosGambit: [[spoiler:Sigma]] pulls one here; if either the Maverick Hunters or Repliforce wins, he can aim the Final Weapon on Earth. The only reason he plans fails was because [[spoiler:General survives his fight with X and Zero and stops the weapon himself.]]
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