* AlternateCharacterInterpretation: It's implied throughout the series that Zero regains at least some of his memories. What he remembers and when he remembers it is mostly left unknown, as well as how much any of that memory influences his decisions in any given situation.
** The game more or less spells it out that Ciel has feelings for Zero short of actually confirming it. Fans have then speculated that the final line of the series might have actually been an AnguishedDeclarationOfLove.
** Dr.Weil, even from the start, had pretty warped ideas of right and wrong, blaming the entire Reploid race for the crimes of the Mavericks. It's entirely possible all the suffering and destruction around him at the time (The Maverick Wars, the fall of Doppler Town, the Sky Lagoon Disaster, Repliforce's rebellion, a colony drop, the emergence of yet ''another'' strain of the Maverick Virus, ''and'' a large-scale rebellion by the new generation reploids, all in his lifetime) left him severely unhinged.
* AnticlimaxBoss:
** Elpizo from the second game. If you can avoid his six-orbs energy absorption attack, you can pretty much dodge anything else he throws at you. His second form is arguably even easier, basically being a large floating target in the middle of a large empty walled room with easy-to-dodge attacks. Compare this with the spike-laden stage that you have to traverse to get to him, as well as the BossRush in between. A few blows from your charged Z-Saber will destroy his second form in a matter of seconds.
** Omega plays this straight and then subverts it. His first 2 forms, thanks to the GBA limitations, are slower and predictable than what is implied from the story. His final form, however, is TheBerserker LightningBruiser capable of thrashing you within seconds if you're not careful.
* BreatherBoss: In the first game:
** Anubis Necromancess III's attacks are relatively easy to dodge, although both the Zombies and the scepter deal a lot of damage. The technique of the crushing structures is fairly easy to avoid.
** Fairy Leviathan is arguably the easiest of the four Guardians. She makes up for it later, while Fefnir actually got somewhat weaker.
* BrokenBase: No, really. [[spoiler:Zero's death]] is still a hot debate, no matter the [[{{Jossed}} Jossing]]. And, remember that the ''Zero'' series officially ended ''in 2005''.
** ItWasHisSled: [[spoiler: Thanks to that long-standing argument, no one would be surprised about Zero's fate now.]]
** Well, kind of. [[spoiler: The Official Complete Works didn't really elaborate on his fate, and at best stated that he was missing in space. For a thing that would elaborate on a lot of things in the ''Zero'' mythos, it really seemed to screw up when it came to revealing Zero's fate.]]
* CompleteMonster: * Dr. Weil is notable in being one of the most evil beings in the ''Franchise/MegaMan'' series despite only appearing in a few games. Following the peaceful resolution of the Maverick Wars by the sentient superprogram, the Mother Elf, Weil decided that Reploids needed to pay for their crimes. To this end, Weil corrupted Mother Elf by turning her into the Dark Elf, and triggered the Elf Wars. Weil used the Dark Elf and her children, the Baby Elves, to control Reploids and force them to fight each other in massive battles, which resulted in the deaths of 90% of all Reploids and 60% of all humans. Defeated, exiled and transferred into a mechanical body for his crimes, Weil eventually returned one hundred years later, consumed with a thirst for vengeance directed at all life for the perceived crimes against him. Weaseling his way into becoming the supreme ruler of Neo Arcadia, Weil turns it into a [[DystopiaJustifiesTheMeans dystopian hellhole]]. When he breaks his citizens to the point where they're desperate enough to risk escaping into the wastelands to form their own colony, Weil decides to obliterate their new home with a KillSat. When his KillSat is disabled, Weil attempts to [[ColonyDrop drop it upon the colony]], killing everyone in the region. Cruel, megalomaniacal and displaying an unprecedented level of sadism in the series, Weil reveled in the suffering of others and desired nothing less than to make human and reploid alike feel like their existences were living deaths.
* ContinuityLockout: The four games are so story-heavy that they only really make sense storywise when played in order back-to-back. The DS CompilationRerelease thankfully makes this a lot easier.
* DracoInLeatherPants: Weil gets plenty of fans agreeing with his original motive, given the tragedies he'd endured. While one can't blame him for despising ''Mavericks'' and being disgusted that many of ''them'' got off scot-free, (such as the ones who chose of their own accord to rebel and cause destruction) holding the entire ''race'' responsible, including the Reploids who had never been Mavericks in the first place, and the Maverick ''Hunters'' who did everything they could to ''fight'' the Mavericks was beyond dangerously ignorant, and a testament to how twisted he had become.
* EnsembleDarkHorse:
** Harpuia. Also one of the most well developed characters in the franchise, which contributes to this.
** Omega, one of the more popular villains in the Mega Man franchise. Popular enough to come back as a bonus boss and an [[InfinityPlusOneSword infinity plus one artifact]] in ''VideoGame/MegaManZX''.
* EvilIsCool: Copy X's armor would spectacularly break any ''VideoGame/MegaManX'' game, essentially being ''X5's'' [[GameBreaker Falcon Armor]] with extra firepower and Charge Man's weapon thrown in for fun.
* FauxSymbolism:
** At the end of the first game, Cyber-Elf X starts projecting an image of himself in a blue robe when talking to Zero. A Cyber-Elfy halo appears above his head in this form.
** Copy X, even moreso. If his first form full of angelic wings aren't enough, in his OneWingedAngel form, he almost literally turned into a seraphic angel. Add to the fact that he's fighting Zero, a crimson-horned reploid.
*** Given the way Copy X acts and his sinister eyes, his transformation is closer to a FallenAngel.
* FanficFuel: The ending of the series. [[spoiler:The fans don't seem to accept Zero's death, and as Dr. Weil cannot die, they "know" he's still out there... There's also the fact that there's around a century or two of TimeSkip between this series and ''MegaManZX''.]]
* FoeYay: Three of the Four Guardians have this going on with the titular Zero (the ones that isn't Phantom).
* FunnyAneurysmMoment: The antagonists of the first three games in this series all have the Greek letter Omega [[BroughtToYouByTheLetterS as their symbol]]. Sure most of them are {{Knight Templar}}s, but they still [[WellIntentionedExtremist mean well]], fighting for the sake of humanity. But later we're introduced to an actual character named Omega, who is everything that the antagonists (except one) ever stood against.
** Somewhat related: in ''VideoGame/MegaManX2'', Zero, [[spoiler:freshly BackFromTheDead]], ''very easily'' destroys a weak clone of himself that the BigBad made. Cue the third game, where [[spoiler:Omega (the same one mentioned above) is the original body of Zero, while ''TheHero'' is the clone]]. But it was subverted, [[spoiler:the clone Zero didn't mind the irony of the situation he was in, and goes on to defeat Omega Zero ''easily''. Also, TheHero may be using a duplicate body, but the mind is real; he is still the ''real Zero''. Omega Zero is now just a mindless puppet]].
** This line loses some of its humor if you consider the only girl he's ever [[VideoGame/MegaManX4 been shown with...]]:
-->'''Resistance Girl:''' You're terrible! Even though you've kissed me before...Shoot, you probably forget every girl...
* GoddamnedBats: The spiked wheel enemies. They are inordinately tough (two saber slashes when one will do in most anything else that moves), coming rolling from offscreen towards you (or occasionally from behind) with no warning, do a ridiculous amount of damage (more than virtually any other normal enemy), move just fast enough that it would take split-second reflexes to dodge them, spawn again if you move mere ''pixels'' backward from where they appeared, and are sometimes dropped in by lifter robots for added cheapness.
* GoddamnedBoss: Volteel Biblio of the third game; a large portion of his fight is akin to a whack-a-mole, except that the holes are spread far apart. His head will appear in one hole while his tail will appear in another, shooting a slow homing ball of electricity.
** Pegasolta Eclair of the fourth game has a clever but annoying tendency to fly up to avoid your attack. He can only be attacked if he's attacking, which you'll have a hard time with since spends most of his time far from the ground.
** Mino Magnus of the same game, while not that hard, it positively annoying: He's weak to ice attacks, but his hitbox is often obscured by his invulnerable shoulders. His magnetizing GrappleMove will cripple you and make you more vulnerable to his magnetic attacks, and his DetachmentCombat attack needs quite the timing and fingerwork to avoid.
* HarsherInHindsight: In ''VideoGame/MegaManX4'', This exchange is made by Sigma and the General in regards to humanity's views on Reploids when the former was trying to recruit the latter:
-->'''Sigma:''' It's about the Maverick Hunters, General. They are far too eager to please the humans and hunt down the Reploids! Do you believe they pose a significant threat?!
-->'''General:''' Perhaps...
-->'''Sigma:''' You already know the truth, General! Their sole mission has been to destroy any Reploids who fail to do as the humans order!
** As this series, and especially Dr. Weil's speech to Zero in ''Zero 3'' showed, Sigma actually turned out to be ''right.''
-->'''Dr. Weil:''' Hehehehe...How pitiful. Of course, a Reploid like you would never understand. The joy of ruling all that you see...Only a human could possibly understand!
-->'''Zero:''' A...human?
-->'''Dr. Weil:''' That's right! I'm a bona fide human. The creator of Reploids...A human being!
-->'''Zero:''' ...
-->'''Dr. Weil:''' The desire for power. The joy of making everything work for you. You have no way of experiencing this without a human brain. It's the ultimate joy! No mere Reploid could ever understand!
** ''That being said,'' Sigma (and by proxy, Weil) was only ''partially'' right - there's obviously ''some'' humans who think like that, but in this series, considering all of Neo Arcadia's propaganda, who would blame them? To say that all HumansAreBastards in this instance would be to use the same fallacy that Yggdrasil used in Anime/DigimonSavers (using evidence of the actions of one CompleteMonster[[note]]who, amusingly enough, was a ''lot'' like Weil[[/note]] to tar humanity with the same brush). Plus, part of Dr. Weil's motivation (according to the supplemental material and before he jumped off the slippery slope) was that he was getting back at the Reploids for their constant violent uprisings, [[SelfFulfillingProphecy which were heavily precipitated by the Sigma Virus.]] Of course, his logic is no different as Sigma's, tarring ''repoidkind'' with the same brush by holding the entire race responsible for what terrorists and criminals members of their race have chosen to do.
* HilariousInHindsight: Zero gets involved in a [[LaResistance rebellion]] in order to take down an oppressive government. [[Anime/CodeGeass Now why should]] ''[[Anime/CodeGeass that]]'' [[Anime/CodeGeass sound familiar?]]
* ItWasHisSled: Dr Weil and Copy X's very existences are common knowledge by now. [[spoiler: And, as mentioned above, Zero's DyingMomentOfAwesome.]]
* ItsHardSoItSucks: Regarded as this by some, to the point that the DS CompilationRerelease includes an "Easy Scenario" with includes lots of 1-ups and all of the cyber-elves. You can still die even in this mode, given how NintendoHard it is.
* LoveToHate: Ask any of Weil's fans, they'll say how horrifically despicable he is (and how he never suffers VillainDecay unlike previous {{Big Bad}}s) what makes him such an effective villain. Omega gets this as well, because of his sheer coolness.
* MoralEventHorizon: Copy X was just more of being morally ambiguous in the first game (performing genocide on Reploids because of the energy crisis, supposedly for the better for humanity). However, in the third game, he's willing to launch a missile to a city block full of innocent humans just to obtain the Dark Elf. At this point, HeroAntagonist [[NobleTopEnforcer Harpuia]] can't stand it anymore and defects from Neo Arcadia. A bit later, when Copy X and Weil contact the resistance to cooperate, [[RebelLeader Ciel]] cites this event as why they can't be trusted. To be fair, Copy X is reborn as Copy X Mk. II by the ObviouslyEvil Dr. Weil and he also manipulates Copy X to do so. Clearly Weil must have done things in him, including the ElectronicSpeechImpediment and [[spoiler:the booby trap implanted in his body which activates when he goes OneWingedAngel]].
* PlayerPunch: Elpizo aims for getting the Dark Elf, and to do so, he had to destroy the [[SealedInsideAPersonShapedCan seal]], X's body. [[spoiler: When Zero finally catches up to him near the seal, he [[ForcedToWatch forces Zero to watch]] by binding him with the Baby Elves' powers as he stabs X's body, destroying it and releasing the Dark Elf.]]
* RoboShip:
** Ciel with Zero...maybe...well, it ''is'' a popular pairing.
*** ShipTease: ''Lots'', which warranted the RoboShip "theory" above. In fact, some of the tropes listed in her bio are ShipTease in themselves (AngerBornOfWorry and the TearJerker, anyone?).
*** FanPreferredCouple: Thanks to the large amounts of the aforementioned ShipTease (whether it's a case of RelationshipWritingFumble or not), many fans warm up to the pairing better than the more "canonical" Zero/Iris. Then again, [[StrangledByTheRedString regarding the latter pair...]]
*** {{Starboarding}}: Unfortunately, because of Zero's mentality in this department, fans have settled for this.
** Neige with Craft, the most blatant example in the ''entire [[strike: series]] franchise'' (besides [[VideoGame/MegaManX4 Zero/Iris]]).
* RonTheDeathEater: A rare canon (at least, WhatCouldHaveBeen) example: [[spoiler:X becomes a tyrant KnightTemplar dictator and Zero is the hero with a different body. Though probably Keiji Inafune had a reason for X becoming bad...at least, we can see the potential of it from the backstory for this game.]]
* SavedByTheFans: X. Not from death per se, but from being an AxCrazy dictator. Similar to what happened to [[KingdomHearts Axel]], this resulted in his inaction with regards to the Guardians' attempts to kill Zero. The sequels give him other things to worry about and the issue really doesn't come up again.
* ScrappyMechanic: While the Cyber-Elf mechanic isn't bad by itself, the first game punished the player with a lower rank for using them ''at all'' despite them being a major selling point. Later games toned this aspect down by only punishing the player for using the more GameBreaker Cyber-Elves, and finally just giving the player one Cyber-Elf that they can upgrade however they want, and only punishing them for overpowering it.
* SignatureScene:
** First game: The fights against the first boss and Copy X.
** Second game: The first level, remembered for its music. Also the [[spoiler:"Elpizo stabbing X" scene and the subsequent TransformationSequence of Elpizo]].
** Third game: The fight against Omega and TheReveal that [[spoiler:he is in Zero's original body.]]
** Fourth game: The fight against [[BigBad Dr. Weil's]] final form, and the final scene, [[spoiler:a shot of Zero's broken helmet to confirm his HeroicSacrifice.]]
* SpiritualAdaptation:
** CasshernSins is often called "the Mega Man Zero anime".
** MetalGearRisingRevengeance can be deemed as a 3D Mega Man Zero game because of their many similarities.
* ThatOneAchievement: Getting the 2 minigames in the third game requires you to beat the game with perfect 100 points in your average score. This means completing ''every'' mission perfectly - complete every subobjective, beat levels quickly, kill a minimum amount of enemies and take no more than a small amount of damage. Oh, and not using your elves (at least not the Fusion ones) or entering Cyberspace.
* ThatOneBoss:
** Aztec Falcon: As he's the second mission boss, you'd be fighting him with minimal abilities (unless you spend a lot of time grinding somewhere else; in Hard Mode, you can't even grind), his boss room is rather narrow, and his attacks cover a lot of space. His wings are also invulnerable, making it harder to hit him when he shoots arrows from his wings.
** Phantom is this when compared to the other Guardians. Unlike the others, he's NonElemental, thus he has no weakness. You can interrupt most of the other Guardians' attacks; for Phantom, you can only intercept his DashAttack. He also plays it nasty with said attack - if you jump over it, he'll quickly dash back to you; if you interrupt it, he may sometimes resume the attack. He also has a DoppelgangerSpin attack where, if you hit the wrong Phantom, he'll do a powerful counterattack; he might also quickly dash at you if you're close to the real him. During the second fight with him, he has a KaizoTrap attack should you defeat him. In the secret fight against him in the third game, a number of his attacks are upgraded - his FuumaShuriken move shoots spreads of kunai multiple times, and his zigzag floating move has him spamming spreads of kunai while floating.
** Kuwagust Anchus from ''Zero 2'' becomes nigh-impossible on Hard Mode if you have an A or S rank. He moves quickly and his grab moves are hard to avoid, especially one that comes after he sucked you in with his tornado. His A/S rank attack is really hard to dodge: He has to be attacked, ''in-flight'', to avoid taking damage, while you're troubled with the wind blowing against you. You have to attack him ''enough'' or you'll eat quite some damage. [[GuideDangIt The game doesn't hint at that at all.]] Or you can just hit him once with chain rod with right timing to derail his attack, as shown [[https://www.youtube.com/watch?v=GiQm2R4PcXQ here]].
** Phoenix Magnion from the same game is also positively confusing. He'll avoid your initial attacks and then counterattack with one of his own, at random. He's fond of TeleportSpam, especially after you attack him. He can only be attacked while he's launching an offense of his own. Worse, the area has "holes" where blasts of magma will shoot out at intervals; during your first fight, depending on which room you're fighting him, the holes are either scarce or covering the entire floor. During the rematch, the design is ''always'' the latter one.
** Heat Genblem from the fourth game. One of his strategies is to walk slowly towards you, then quickly defends with his shell if you attack. Keep attacking and he'll counter with an ElementalPunch. Another of his hard strategy has him floating next to one of the walls, then firing a continuous laser beam while spinning; you have to follow through or you'll get hit. He's rarely open to attacks, and when he is, you'll have a hard time dodging him to actually attack. To top it all off, thunder attacks (his weakness) are rather weak in this game.
** Also Craft of the same game; he has a plethora of attacks that will limit your space. Especially, his bayonet attack deals quite some damage if you get hit (and it bypasses MercyInvincibility, too), and his sniping laser would need a split-second timing to dash under (unless you have the DoubleJump chip). He also has an evasion move where he can go through you. In the second fight, his EX Skill is a MacrossMissileMassacre that can cover the entire screen unless you can slice a few of the missiles.
* ThatOneLevel: Neo Arcadia Shrine, part 1. [[GoddamnedBats Those.]] [[PlatformHell Fucking.]] [[PunctuatedForEmphasis BIRDS!!]]
** And that's not all. {{Temporary Platform}}s abound. Temporary Platforms that have no side grip, ''shoot bullets downward'', leave no margin for error, and are placed above enemies which you will likely land on should you fall. There's also ''three bosses''.
** Neo Arcadia ''Tower'': SpikesOfDoom. EVERYWHERE!
** One of the most infamous missions in the series is a Protect the Factory section from the first game. After beating the boss, you need to find and disarm 8 bombs scattered around the level. Finding the bomb locations isn't a hard task by any means, but three of them are placed in a very tricky spot - a section with floating platforms and lots of [[GoddamnedBats flying enemies]]. The main problem comes from the small field of view and inability to look around, all of which leads to constant leaps of faith and mission retries after yet another failed landing. It's also the only level in the game that starts right from the boss fight, which more likely means developers ''knew'' that the mission is already hard as hell, so they save players trouble of completing the bomb section from the start after losing the boss battle.
** ''Zero 2's'' Power Room stage, filled to the brim with lava and exploding Telebombs and not much room to maneuver. The stage design is very different from the others, where you have to find 4 chambers with generators; it doesn't have a finish, and you only fight the boss when you destroy the final generator. And to top it off, the boss is an absolute nightmare. Worse still, one of the Cyber Elves hidden here is pure GuideDangIt material. You essentially have to play ''SpaceInvaders'' in one section, kill every enemy while being blocked by moving platforms that hurt you if you touch them, and after that have to hit the fast-moving UFO in the three seconds from when it emerges to when it leaves.
** The Bombardment Aircraft. You start off leaping between moving shuttlecraft which ''shoot at you'' while you're using them as platforms, on top of Pantheons shooting at you on top of them, requiring perfect timing so as to not to be knocked into the massive BottomlessPit. Once past that section, you have to fight a miniboss who fires fast-moving, area-damage missiles at you until you hit it. When you hit it, it drops a row of bombs which can only be avoided by standing exactly where it was previously hovering. Then you navigate through a series of timed stage hazards that will eat right through your tiny lifebar and require expert timing to pass unharmed. ''Then'' you have to do a HoldTheLine section protecting Ciel for 90 seconds, which counts for basically your entire mission score. If she gets hit, goodbye A or S rank. Naturally, this is a BulletHell sequence plus the Pantheons who you have to hit while blocking every bullet. This also ends with a very powerful boss.
** There's also the Shuttle Factory, which is also long, contains lots of lava and other stage hazards, and a tough boss fight against Fefnir at the end.
* ViewerGenderConfusion:
** Harpuia's voice is Creator/MegumiOgata, a woman. Plus his name is derived from the legend of the Harpy, half bird, half-''women''.
*** It does not help that he's wearing the exact same clothes as Leviathan (the female Guardian) with a PaletteSwap (what appears to be a [[BareYourMidriff midriff-baring shirt]] and...panties).
** Cubit Foxtar, possibly overlaps with ShesAManInJapan.
*** Made more confusing by being based on a Kitsune, which can change genders. Makes more sense if you assume that his inhuman battle form is his true form.
** There's also Anubis Necromanc''ess'' (boss in ''Zero 1'' and ''3''), confirmed to be male [[note]]His name in Japan is Anubistep Necromances, with one "s"[[/note]], and Polar Kamrous (in ''Zero 2'') which, despite the matching build and deep voice, is female.
*** Weirdly enough, the Complete Works book refers to Kamrous as [[FlipFlopOfGod male.]]
* WhatDoYouMeanItsForKids: The entire series qualifies, for the reasons listed on the [[NightmareFuel/MegaMan Nightmare Fuel page for the entire franchise]]. There's also the fact that the Neo Arcadian government basically does a systematical genocide on Reploids to solve energy crisis. And the game is rated E.
* TheWoobie: Ciel gets extra points for this. In two separate occasions, she thought that she was doing the right thing, but it only ended up giving rise to worse problems. The first one would be for creating Copy-X, and we all know how that turned out. The Resistance is partly her effort to make amends for what she's done. The second time was successfully researching an energy source that she believes would put an end to the war, only for it to be a catalyst to a new conflict. Mind you, this is a person who longs for peace as much as X, and she is very young at the series' start, and also human. And, then there's the fact that, at series' end, [[spoiler:she is waiting faithfully for Zero to come back, when it was completely impossible.]]
** Alouette is implied to have gone through a BreakTheCutie livelihood, and might have suffered even worse, if Ciel hadn't found her.
** For the record, how about [[KickTheDog poor]], [[KilledOffForReal poor]] [[BigGood X]]? [[spoiler: Let's just put this in review: The only cure for the virus they had worked tirelessly looking for for well over a centuy is weaponized into a living maverick-maker. His best friend's body is stolen and converted into an ultimate weapon that wipes out most of the planet's already-perilous population. His best friend goes into an intended-eternal stasis, leaving X with basically no shoulder to lean on. He's forced to manage the virtual entirety of the world's remaining population and all maverick activity by himself. He is forced to effectively kill his body to seal the aforementioned corrupted cure which not only leaves him off, but his soul is split into fifths. X is forced to watch as the Copy made to take his place ruins the haven he'd so desperately fought to preserve, and his "offspring" are tricked into being assassins and strongarms for the sociopathic copy. Finally, X is murdered in his comatose state by some minor villain who just wanted the Dark Elf. He did not even get a chance to fight back. He finally spends the rest of the following game slowly, slowly dying and using every precious ounce of power for the sake of others.]] Jeez, man.
** IronWoobie: Almost all the tragedies in the ''X series'' are inflicted on Zero, and even more are piled on here. Like the fact that [[spoiler:he wakes up seeing the current state of the world, and freshly awoken, he has to continue fighting, ''again'']], and [[spoiler:he was able to finally return the world to a peaceful state, which was what he and X have been fighting for a long time, only for him not to see it come to fruition, seeing as ''he's dead''...]]
** StoicWoobie: After looking at Harpuia's motives, personality and the situation he's in, it's pretty easy to feel sorry for him.
** Reploids are turned into a WoobieSpecies by Copy-X's actions, and while basically turns everything into a CrapsackWorld.
* {{Woolseyism}}: Some of the boss' names are changed overseas. In particular, Dr. Weil's name was originally Dr. Vile. There's already [[VideoGame/MegaManX another guy who's named Vile]] (who is originally called [[Franchise/StarWars V]][[ShoutOut A]][[WritingAroundTrademarks VA]]), so the name change is to avoid confusion. If pronounced in German, it can still be read as "vile". There's also the fact that it's quite meaningful in it's own right (being the BigBad, Dr. Weil is the Dr. Wiley of the Zero series).
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