Ninja Gaiden

Ninja Gaiden is a series of video games originally developed by Tecmo. Released first as an arcade title, it made its way to the Nintendo Entertainment System, Nintendo Game Boy, TurboGrafx-16 and Sega Master System, then was revived for the Microsoft Xbox under Tomonobu Itagaki's "Team Ninja", the same creators and designers behind the Dead or Alive series. The NES games are hailed for being among the first to use a video game as a vehicle to tell an elaborate story.

The main character is Ryu Hayabusa, a Ninja and member of the Dragon Clan, who gets into government conspiracies, kicks loads of ass and slaughters legions of supernatural beings along the way.

Ninja Gaiden Trilogy
In the first game, Ryu receives a letter from his father Joe Hayabusa, saying that should he not return, Ryu is to journey to America and contact a man named Walter Smith. Believing his father dead, Ryu goes to America to carry out this request. After battling a large man with an axe in a bar, he is subdued by a woman with a tranquilizer gun. He awakens in a prison cell, where the woman (Irene Lew) frees him and gives him a mysterious, grotesque statue. Ryu is puzzled by this, but presses onward. He meets with Smith, who identifies the statue as one of the Demon Statues, a pair of Artifacts of Doom he and Joe discovered and vowed to protect. As Ryu and Smith talk, the statue is stolen by another ninja. Ryu gives chase, and recaptures the statue, but returns to find Smith dying. Ryu vows to carry on his work, protecting the Demon Statues.

However, Ryu is captured by the CIA and brought before A. Foster, the head of the agency. Foster reveals that Irene is one of their agents, and that she is tracking down a man known as Jaquio, who seeks to release the powerful demon sealed in the statues. Foster orders Ryu to take out Jaquio; Ryu, remembering his oath to Smith, complies. Air-dropped into the jungles of Brazil, he makes his way to Jaquio's fortress, where he finds Jaquio has Irene at gunpoint. Jaquio reveals he has the second Demon Statue already, and demands Ryu's statue in exchange for Irene's life; Ryu, being new at the whole hero thing, complies. Jaquio's an old hand at villainy, however, and simply absconds with the statues and the girl... but not before sending Ryu hurtling down a Trap Door to the catacombs below.

Undaunted, Ryu fights his way to the top of the fortress, where he again encounters Jaquio and Irene... as well as Ryu's father, who, while not dead, is under Jaquio's mind control. Ryu gets the better of Jaquio in battle, and in desperation, Jaquio launches a magic bolt at Ryu, but his father comes to his senses, intercepts the bolt, and dies. The enraged Ryu proceeds to kill Jaquio... but he's too late, for Jaquio has released the demon from the statues!

Ryu bravely fights the demon, sealing it once more. After the battle, Foster radios Irene and orders her to assassinate Ryu and take the statues. Irene hesitates, and Ryu takes her radio and tells Foster the next time they meet, it will be as enemies.

Quite a bit more elaborate than the Save the Princess plots of the day, isn't it?

Ninja Gaiden II: The Dark Sword of Chaos and Ninja Gaiden III: The Ancient Ship of Doom both had similarly complex plots, centered around their titular MacGuffins. Due to space considerations, we won't get much more into detail here; however, they offer just as many, if not more, twists and turns as the first game.

As for the gameplay that takes place between the cutscenes? Ninja Gaiden played a lot like Castlevania... only on steroids and speed. The games were the very epitome of Nintendo Hard, with enemies coming at you from every direction at once. Gamers didn't seem to mind, however: even those who found the challenge to be too much suffered through it anyway to see the next chapter in Ryu's saga.

Aside for a compilation of the trilogy on the Super Nintendo Entertainment System, the series was silent, until Ryu was added to the roster for Team Ninja's Dead or Alive series, where Ryu's basically the only male character people seem to like as much as the girls.

Ninja Gaiden Trilogy (Post-2004)
Sometime in 1999, Itagaki and Team Ninja began work on their first "action" title, aside from their on-going Dead or Alive series. Although then-Tecmo wanted a tie-in for this new revival with the NES trilogy, this Xbox version of Ninja Gaiden, released in 2004, involves none of the elements. In an interview, Itagaki mentioned he "prefer not to be influenced by or base it on the original story". While Ryu's still the protagonist, none of the above elements are explicitly mentioned.

The story establishes Ryu's a member of the Dragon Ninja Clan, charged with protecting the Dark Dragon Blade, a BFS imbued with some pretty extraordinary powers. After the game's tutorial level, he's informed that the Hayabusa Village has been destroyed. When Ryu investigates, a samurai pledged to the Holy Vigoor Emperor, Doku, kills him with the Dark Dragon Blade.

Don't worry, he gets better.

Thus, the game embarks Ryu upon a ferocious quest for revenge and the retrieval of the Dark Dragon Blade. The details of the plot are convoluted and don't add up to anything particularly extraordinary, but Ryu slices and dices his way through Vigoorian soldiers, tanks, zombies, ninjas and ghost piranhas.

The Xbox version is, as the kids these days say, difficult ...really, really difficult... as in "throw-your-controller-at-the-screen-and-scare-the-dog difficult". In contrast to other Hack And Slashers, enemies avert Mook Chivalry and have no compunctions about suffocating the player at every available moment. In fact, beating this game is an achievement. Hell, there was an Updated Rerelease called Ninja Gaiden Black which not only fixed gameplay imbalances, placed more enemies and bosses and added in "Combat Missions", it included two new modes: a "super-duper-mega-easy" mode and an "even harder than Harder Than Hard mode"! Unfortunately, it didn't help the "super-duper-mega-easy" mode was quite hard itself, difficult to the point of inducing trauma.

The game was critically acclaimed by all, with many praising its preserved difficulty from the NES trilogy, alongside gorgeous visuals and attention to detail in combat and environments by pushing the Xbox beyond its hardware limitations. An Enhanced Remake of Ninja Gaiden Black called Ninja Gaiden Sigma for the Sony Play Station 3 was released in 2007, rounding out the last gameplay additions with a new character, new weapons and enemies, while making it look more pretty with the console's high-definition capabilities. It also removes or simplifies some puzzles that contained too much back-and-forth.

In 2008, Ninja Gaiden: Dragon Sword was released for the Nintendo DS. This Gaiden Game sequel set six months after Ninja Gaiden tells of Ryu and his journey to find the Dark Dragonstones that can resurrect an ancient Dark Dragon. In the same year, the true sequel Ninja Gaiden II was released for the Xbox360, where another Artifact of Doom the Dragon Lineage were guarding, the Statue of the Archfiend, is stolen. Ryu must travel the world chasing the Four Greater Fiends as they attempt to resurrect the Archfiend itself. Both games retain the difficulty of Ninja Gaiden (Ninja Gaiden II arguably even harder) and the stories are serviceable, yet the latter's almost completely nonsensical, with Everything Trying to Kill You more aptly applied. For example, at one point, a giant armadillo with marginal fire Elemental Powers appears with no apparent connection to the villains.

Following the release of Ninja Gaiden II, Itagaki stepped down from Team Ninja and left the now merged Tecmo Koei. Current series director and producer Yosuke Hayashi took over and released an Updated Rerelease of Ninja Gaiden II on the Play Station 3 as Ninja Gaiden Sigma 2. Notably, the game partly resolves the nonsensical nature of the plot in the 360 original, but also throws in new characters and scenarios, a co-op mission mode, a "Chapter Challenge" mode and a prologue that links Dragon Sword to current continuity (Ninja Gaiden II never makes a mention of Dragon Sword). It also significantly tones down the 360 game's gore and the number of enemies, making them more resilient instead.

Ninja Gaiden 3 was release in March 2012 on both Playstation3 and Xbox360. Team Ninja's also considering a release on the Nintendo Wii U, under a new heading Ninja Gaiden 3: Razor's Edge. Contrary to his predecessor, Hayashi wants to make the game "more accessible" with the inclusion of the optional "hero play-style", which provides an auto-guard at low health for beginners. Long time fans are quite displeased with this choice, although the game itself is still harder than average. For the first time in the series, Ninja Gaiden 3 features Competitive Multiplayer. Set some time after Ninja Gaiden II, Ryu receives a request from the Japanese government, after terrorists take the British Prime Minister hostage, demanding his appearance. He travels to London and faces the mysterious foes, led by the enigmatic "Regent of the Mask". During their fight, the man places a curse on Ryu's right arm, making him feel the pain and hatred of the people he killed.

Ninja Gaiden 3 also marks the return of scriptwriter Masato Kato to the series, to bring back the sort of deep narrative seen in the NES trilogy. It effectively ties the modern games into overall continuity. The action also has a much more cinematic and dramatic feel than the first two games.

Alas, the third game received very mixed reviews overall (including a memorable 3/10 on IGN!), criticizing the heavy use of Quick Time Events and an excessively streamlined gameplay compared to the previous titles, among other things.

Now with a good Character Sheet, character tropes go there.

""Another intruder has been detected with explosives. A blonde woman. Message to all units: she's hot!""
 * Absurdly Spacious Sewer: The tenth level of the Xbox title, oddly named "the Aquaduct" (sic).
 * Action Girl: Although this series falls for the Faux Action Girl a little bit too often, Ayane, Momiji and Rachel in Ninja Gaiden Sigma 2 definitely play the role straight.
 * Irene Lew should count. Those times when she isn't already captured, she can definitely hold her own. She even pulls her own Big Damn Heroes.
 * Adaptation Dye Job: Irene Lew, brunette in the classic NES trilogy and Original Video Animation, blonde as of Dead or Alive: Dimensions and the Xbox series too under her alias.
 * Alien Sky: As Ryu approaches the gate to the Realm of Chaos, he's greeted by an eerie violet sky with strange stars hanging too close to the surface.
 * Anachronic Order: Some Continuity Snarl and Flip-Flop of God aside, the series goes like this, from a young 18 years old Ryu to a 23 years old Master Ninja:
 * Ninja Gaiden Shadow (Game Boy) --> Ninja Gaiden (Xbox) --> Ninja Gaiden: Dragon Sword (Nintendo DS) --> Ninja Gaiden II (Xbox 360) --> Ninja Gaiden 3 (PS3/Xbox 360) --> Ninja Gaiden (NES) --> Ninja Gaiden III: The Ancient Ship of Doom (NES) --> Ninja Gaiden II: The Dark Sword of Chaos (NES) --> Ninja Gaiden (OVA) --> Dead or Alive series.
 * And Your Reward Is Clothes: Beating any of the difficulty levels in the Xbox series rewards the player with a new costume.
 * Anti-Hero:
 * Ryu in the modern trilogy is pretty much established as this. Although he does have a strong sense of justice in his mission to punish evil, he has no qualms about killing ninjas from other clans and soldiers alike; in fact, it's made clear he has no hatred nor even a slight dislike towards any of them (only some Fiends get to provoke Ryu's wrath). Ryu faces this as the harsh reality of a ninja's upbringing... death is a natural part of their world even against friendly rivals.
 * A notable mention goes to the first Ninja Gaiden for Xbox: in the first mission, Ryu slaughters as many ninjas as he can find for his training routine, and they were from a friendly clan ; the first ninja Ryu ambushes is also his first kill in the game. Ryu's reaction to his fallen foe is that of simple acceptance, since it was the right thing to do and the fallen ninja wouldn't live much longer anyway if he was that weak.
 * In the sequel, after having mowed down hordes of Black Spider Clan ninjas and Fiends, Ryu still pays his condolences to all the fallen who went against his clan and then walks away for his next mission.
 * Ninja Gaiden 3 uses this trope as its primary theme: as a "Japanese dark hero", Ryu's remorseless "cut down the many for the sake of many more" routine is coming back to bite him in the ass due to the "Grip of Murder" curse that relates to the amount of lives he's taken throughout his life. In one scene, a mercenary begs not to be killed because he has a family to go home to. While it seems the game tries to give the player the option of taking a life, the button prompt says otherwise and Ryu cleaves him in two.
 * Anti Frustration Feature: Ninja Gaiden 3 allows the player to switch anytime to "Hero mode". The game plays the same as in Normal, but when health is under 30% (when the lifebar starts to glow red), guard and evading become automatic, making death pretty much impossible.
 * Artifact of Doom: The Dragon Ninja clan apparently exists to look after these, keeping the lids on various cans of Evil
 * They ain't too good at it though, considering how everybody but Ryu gets pwned. Twice.
 * Artificial Stupidity: The T-Rex boss in Ninja Gaiden 3 is becoming quite infamous for this.
 * Attack Drone: The Shadow Clones from The Dark Sword of Chaos, which follow in Ryu's footsteps precisely and attack when he does, at no cost. He can have up to two Clones out at a time.
 * Auto Revive: Talisman of Rebirth.
 * Awesome but Impractical: The Unlabored Flawlessness. It's the wooden sword upgraded some 7 times (other weapons peak at 3 or 4) with no discernable change until it becomes a giant wooden paddle. It's a surprisingly powerful weapon, able to wreak havoc at about the same power as the upgraded War Hammer, but it's high upgrade cost and very restrictive secret to its power (when you're low on health it becomes exceptionally vicious) makes it difficult to use.
 * The Falcon's Talons Ultimate Technique is generally regarded as one of the worst in the entire game, (the talons themselves are very restrictive to close combat as well), but it is awesome to see Ryu Hayabusa go berserk on an enemy with claws attached to his hands and feet.
 * Projectile weapons in the first Xbox game start bouncing off of enemies when you get near the end (so much for your giant shuriken and stocks of gunpowder laced kunai...). The bow is an exception, but standing around for Ryu to take it out and fire gets you killed pretty quickly.
 * Awesome McCoolname: The name of the stages in the original trilogy were pretty cool. One such name is Place of Red Execution, in which Ryu fights Bloody Malth in the first NES game.
 * Back for the Dead: in the NES games.
 * Back from the Dead/Disney Death:
 * Ryu after being killed by Doku in the Xbox game.
 * Irene Lew after being sacrificed for Jacquio's goal in The Dark Sword of Chaos, she gets resurrected by the Dragon Sword's magic.
 * Badass: You have to be one in order to be able to beat the game.
 * Badass Long Hair: Ryu's first appearance in the Dead or Alive series had him long haired enough to keep a ponytail, and he showed up like this again in Ninja Gaiden: Dragon Sword which also marked his debut unmasked appearance in the new series.
 * Bag of Spilling: In the Xbox games, it is averted for Ryu's moves: you start Ninja Gaiden II with the Flying Swallow, the Izuna Drop, the counter and the Guillotine Throw, all of which were acquired during the first game. Played straight for the weapons in a strange way: three of the weapons you find in random places (the Lunar, Dragon's Claw & Tiger's Fang and the Vigoorian Flail) were already found in the first game, and the first two are supposed to be unique…
 * Bait and Switch Gunshot: After beating first boss of Ninja Gaiden II: The Dark Sword of Chaos, Ryu meets a mysterious army operative who pulls a gun on him. Before Ryu can react, the man shoots! ...to finish off the monstrous Dando the Cursed, who Ryu hadn't quite finished off.
 * Barbie Doll Anatomy: When she shows up in one cutscene wearing nothing but blood, Elizabét appears to be missing something...
 * Battle Couple: Ryu Hayabusa the Badass One-Man Army Ninja and Irene Lew/ the Girl With Guns then later Mission Control; still together in the Dead or Alive series.
 * Beam Spam: Dagra Dai, so much.
 * Beat Them At Their Own Game: A villainous version. Most of the bosses in The Ancient Ship of Doom use Ryu's Ninja Arts such as the Windmill Throwing Star or mass-fire versions of the Art of the Fire Wheel.
 * BFS: Dabilahro from the Xbox title; also, cleavers used by Fiend Nightmares; then, there's Spirit Doku's nodachi. And of course there's the Dark Dragon Blade itself.
 * The final boss in the unjustly-overlooked arcade original had a pair of these.
 * Ninja Gaiden II features a scythe that, through upgrades, is about the size as Ryu himself.
 * Dagra Dai Dual Wields these.
 * The titular Dark Sword of Chaos is just gigantic. And yet Ashtar can wield it easily in one hand.
 * Big Bad:
 * Jaquio in the first NES game.
 * Ashtar in The Dark Sword of Chaos, the second NES game, and the orchestrator of the events of the first. His position gets hijacked when.
 * in The Ancient Ship of Doom, the third NES game, after double-crossing his boss.
 * Bishonen: Ryu's design for Ninja Gaiden: Dragon Sword, add to the fact it was the first time he appeared unmasked outside the Dead or Alive series after Itagaki's new direction of keeping Ryu always masked in his main games. The ninja became a pretty boy, albeit still with a toned body and packing a strong voice, in the DS release.
 * Blind Idiot Translation: Basaquer, Kelbeross, Malth and even Big Bad Jaquio fall pray to this in the original NES trilogy: their actual names were supposed to be "Berserker," "Cerberus", "Mars" and "Devil King" (Jakiō). The mistranslated names do have plenty of charm though...
 * "Dando the Cursed", the Act 1 boss in Ninja Gaiden II for the NES, is supposed to "Damned".
 * Blood Bath: The female villain in Ninja Gaiden II for the Xbox 360 is seen bathing in a pool of blood at one point and is even named "Elizabet" as a Shout-Out to Elizabeth Bathory.
 * Blood From the Mouth: After a run-in with the newly-resurrected Jaquio in The Dark Sword of Chaos, a heavily-injured Robert is seen bleeding from the corner of his mouth.
 * Bloodier and Gorier: Ninja Gaiden II for Xbox 360. As if the first wasn't gory enough... The third game more or less goes back to the level of the first game by removing dismemberments and decapitations. Although thanks to a new engine, blood will not only stain Ryu's weapon during fights, but also but also his body… and the camera.
 * Ninja Gaiden 3: Razor's Edge is set to bring back all the gore that made Ninja Gaiden II famous.
 * Bloody Bowels of Hell: In Ninja Gaiden II: The Dark Sword of Chaos, the last stages take place in the Realm of Chaos. They steadily become more organic, with pulsing organs and faces on the walls, dripping ooze, and veins running across every surface.
 * Boobs of Steel: As a playable character in Ninja Gaiden Sigma, Rachel relies far more on sheer brute strength than Ryu, and also handles larger weapons better than the initially clumsy Ryu. Her bust size is accordingly massive.
 * Boring but Practical: For the array of awesome weapons that you have stashed in Hammerspace, you'll probably end up being forced to use the Dragon Blade to beat bosses and higher-tier enemies.
 * To a lesser extent, shuriken do virtually no damage but are very useful to stun small enemies and prevent them from grabbing you or interrupting your charge.
 * Boss Dissonance: The first NES game was a Mario type. Barbarian, Bomberhead and Basquer were all ridiculously easy once you got the pattern down, an easily-exploitable glitch could make Kelbeross a pushover, Bloody Malth is just a matter of getting close to him and mashing buttons, and the Masked Devil just requires you to hit the giant clown-nose thing in the middle. Jaquio, however, is ungodly hard, and the Demon is largely luck based. The sequels evened it out quite a bit.
 * This is also the case in Xbox 360 Ninja Gaiden II. While the levels are basically massive gauntlets with endless hordes of cheap mooks, most bosses are surprisingly easy to take down. Even the four Greater Fiends and the final boss pose little threat. The Updated Rerelease Ninja Gaiden Sigma 2 balanced things by reducing the amount of mooks but making most of the bosses harder, improving their AI and their health.
 * Boss in Mook Clothing: Good lord, the Vigoorian Berserkers. They are armed with a Dabilahro, are fairly fast for their build, have a solid guard but are also very resilient, and on top of that have nothing but powerful close range and distance attacks. Of course, if you try to use a Flying Swallow, you will be promptly dissuaded to try again. Manage to deal them enough damage? To reward you, they turn red and become even more dangerous. Granted, there is a simple tactics to take them down (let them attack at close range and use a counter), but it doesn't work so well when there are two or three of them (which is... 90% of the time).
 * Boss Rush: Sort of at the end of the first Xbox game. You first fight two previously beaten bosses, then Marbus, the two forms of the Emperor and the Dark Disciple. In Very Hard and Master Ninja, however, the two fairly easy bosses are replaced by the much more challenging ancient fiends Nicchae and Ishtaros, making this a Boss Rush with only new bosses!
 * Bowdlerise: While Ninja Gaiden Sigma 2 for PS3 brought great additions such as new playable characters, game modes and multi-player option to warrant its deserved critical acclaim, it also got some vocal criticism from some due the direction of removing all the blood bath present in the Xbox 360 version, instead all gallons of blood were turned into purple smoke, which creates a rather odd effect because Ryu still performs brutal actions against his enemies only to see them gush out purple essence. Another less discussed issue was the removal of all the already few puzzles present in the Xbox 360 version, turning Ninja Gaiden Sigma 2 into a non-stop action party.
 * Bragging Rights Reward: In the first Xbox/PS3 game, the Plasma Saber Mk. II (in Normal) or the Black Dragon Sword (Hard and above), sort of. You get them by gathering the 50 gold scarabs, but the last one is so close to the end of the game that they won't be of much use. Add to this that you have to bring the scarabs to Muramasa, and there is no shop at the top of the Emperor's tower (where you get the last scarab). That means you have to go back all the way down and go though several tough enemies and swarms of ghost piranhas just to find a shop where you can get the damn sword. Only to discover that the Plasma Saber is every bit identical to the True Dragon Sword and that you can't use the BDS against the final boss (since he's the one who uses it). So except for some fiend challenges like the ones with many Berserkers, it's not really worth the trouble. This trope is averted with the highest difficulty Master Ninja Mode, which rewards you with… nothing!
 * Brutal Bonus Level: The final mission in the first game, Eternal Legend, is a mini-scenario with 5 phases, during which you face waves of all the enemies met in story mode, and several bosses in-between. You have access to most of your semi-upgraded weapons and unlimited projectiles. You can save and go shopping between phases, but you will have very limited resources, and will have to take as little damage as possible to beat the mission.
 * Camera Abuse: For additional immersion, blood will splat on the screen each time you finish off an enemy in Ninja Gaiden 3. Yum!
 * Camera Screw : In both Xbox titles, the camera will often be your toughest enemy, choosing the most impractical angle possible, zooming without reason and putting the Mooks or even Ryu himself off screen. Surely the PS3 Updated Re-releases have fixed this problem, haven't they? Er… well, no.
 * Fortunately, the camera in Ninja Gaiden 3 does its job decently, although still not perfectly.
 * Canon Immigrant: The fact Ryu married with Irene and opened up a Curio/Antique Shop to run it together in the OVA carries over to the Dead or Alive series which is set after everything that happened in his solo series. After Igakaki's re-imagination for the Ninja Gaiden series on the Xbox, it looked this fact got retconned for good, it took his departure from Team Ninja and Yosuke Hayashi's intervention as the new director to put the pieces back together in Dead or Alive: Dimensions.
 * Looking the other way around, Ayane would be the biggest immigrant in the series. also had a cameo in Ninja Gaiden Sigma 2, although way smaller. See The Faceless below.
 * Cats Are Mean: And those of the first Xbox game are Demonic Spiders!
 * Celibate Hero: Ryu in the present games, Rachel and Sonia are obviously interested on him, Momiji and Ayane might be runner ups, still Ryu shows no response towards any of them. It might be a case of respecting continuity, and Ryu will eventually fall in love with Irene later,, or it's an entirely new continuity and Ryu won't fall for anyone since there's some Flip-Flop of God in regard the present games being prequels for the original trilogy or it is a completely new setting with no relation to previous titles.
 * Worthy noting that most of the Flip-Flop of God came from Itagaki, now that he has no relation to the series and Yosuke has given some continuity nods to the original trilogy. Irene, indeed, might be on the way for Ryu.
 * Chain-Reaction Destruction: Either that or bosses in NES games carry a set of firecrackers which activate upon the death of the boss.
 * Chainsaw Good: Zombies with chainsaws and cannons for arms? Yep, we got 'em.
 * Charged Attack: Collect type only in the first Xbox game. Upgraded to Collect and Hold type in all subsequent games and remakes.
 * Goes back to collect type in Ninja Gaiden 3: you can only unleash a UT when Ryu's arm starts to glow red after killing a few enemies. In the same way, the Ninpo now also requires to fill up a gauge.
 * Charge Meter: Ryu glows brighter and more fiercely as the charge levels up (accompanied by an explosion).
 * Charles Atlas Superpower: "My strength comes from training, not from some curse in my blood." Play the game, get all upgrades.
 * . Also, he wields a massive battle axe/hammer, a great sword explicitly said to be 100 pounds in weight, and a gigantic scythe that he steals from a demon twice his height.
 * Also, he's.
 * Check Point Starvation: Ninja Gaiden Sigma 2 has a few passages where you have to go through several long and tough fights without the possibility to save in-between. Most notably the last parts of Chapter 13 (including the very grueling stairway fight), 14 (the graveyard fights) and the first half of chapter 16 (the very long straight corridor). The latter two get Bonus Points for having an appearance of Recurring Bosses out of nowhere without the usual auto-save. These passages are stressing in Normal, but get really sadistic in Master Ninja.
 * Cherry Tapping: Wooden Sword School.
 * Chest Monster: We found some ghost fish - in a chest! Instead of a box of "cash"!
 * Chickification: Hits Irene Lew hard in the OVA; in fact, she's not even a Faux Action Girl, but a Damsel in Distress from start to finish.
 * Collapsing Lair: A staple of the series once the Big Bad is defeated.
 * Competitive Balance: The weapons in the Next-Gen series use some combination of range, damage, combo potential and the power of the Ultimate Attack. The Dragon Sword is the most balanced but in the first game there are several weapons that mostly play the same way (War Hammer, Dihilabhro and the Unlabored Flawlessness are all heavy blunt weapons, as well as the Dark Dragon Sword in bonus-quests). The second game has a bit more variety in that regard, no two weapons play quite the same.
 * Also used for the girls in Ninja Gaiden Sigma 2: Rachel is the Mighty Glacier, Ayane the Fragile Speedster, while Momiji is Jack of All Stats.
 * Conservation of Ninjutsu: Ryu, a lone Ninja, will slice his way through veritable armies of Ninja Mooks.
 * Continuity Cameo: Ayane from Dead or Alive shows up in both Xbox games, as Ryu appears in Dead or Alive itself.
 * Irene Lew makes a cameo appearance in Dead or Alive: Dimensions as Ryu's CIA contact during the story mode..
 * also has a faceless cameo in Ninja Gaiden Sigma 2.
 * Continuity Nod: With Dead or Alive: Dimensions, it seems Yosuke Hayashi is trying to fix some of Itagaki's mess, Irene Lew making a cameo in particular seems to be an attempt at settling Ryu's appearance in the Dead or Alive series again as being placed years after his solo adventures.
 * In the Ninja Gaiden series itself, Ninja Gaiden Sigma 2 for PS3 gives many throwbacks to both Ninja Gaiden for Xbox and Dragon Sword for Nintendo DS with the inclusions of Rachel and Momiji respectively, something that the original release for Xbox 360 didn't trouble itself with.
 * Though to be fair, a number of enemies in Ninja Gaiden II were taken directly from Dragon Sword (the Rasetsu ninjas and the red dragons, among others).
 * Continuity Snarl: Ryu's appearance in the Dead or Alive series, since the first installment it was made clear in his character bio that the available Ryu is, canonically, the one who already has ventured through all his solo games, reinforced by stating he's a Curio Shop owner, something that would only happen after the end of the NES trilogy with Ryu married to Irene and everything else, namely from the OVA. Itagaki then envisioned the new Ninja Gaiden series for the Xbox and kind of made continuity unstable, such as having Ryu wear his "Black Falcon" outfit as the default outfit from Dead or Alive 4 and onward, while making no mention of Irene or his shop in-game.
 * As of Dead or Alive: Dimensions, things seemed to have been fixed, thanks to a couple of cameos here and there.
 * Convection, Schmonvection: In the next-gen Ninja Gaiden II, Ryu can run on lava! And swim in it for that matter, although it starts to hurt then.
 * This could be averted by the fact that he constantly set's himself on fire every time he uses ninpo (and not just fire) and by the fact that he's a Badass.
 * In the second and third NES games, Ryu can easily cross a firepit or the caldera of an active volcano and won't suffer injury unless he actually falls into the flames or lava.
 * Cosmetic Award: Karma system.
 * Cue the Sun: The Happy Ending of the first and third NES games.
 * Cutscene: One of the first games, if not the first game, to incorporate these in between levels to tell a cohesive story.
 * Damn You, Muscle Memory!: In Ninja Gaiden Sigma 2, the bow is aimed and fired with the triggers instead of O in Ninja Gaiden I and Ninja Gaiden II. Justified since it allows to fire shurikens even with the bow equipped, but it does take a bit of time to get used to it. The opposite way is even worse: in Ninja Gaiden II, many a Ninja Gaiden Sigma 2 player will try to throw shurikens mid-jump and fire an arrow. And get killed.
 * Same deal with the guard button: in the Xbox games, it's on the left trigger; in the Play Station 3 ones, it's on L1. Considering the consequences of letting your guard down for one second in Ninja Gaiden II, this can be a problem.
 * Deadly Lunge: The Flying Swallow and Guillotine Throw techniques can make short work of the standard Mooks.
 * A lot of enemies like to pull these stunts too.
 * Death From Above: A gameplay mechanic in Ninja Gaiden 3. You can jump from a high building and glide in the air towards the poor mook, before impaling him as you land.
 * Desperation Attack: Unlaboured Flawlessness.
 * Did Not Do the Research: In-Universe, there's a plaque on Liberty Island on which Ryu remark, "They are teaching the ways of the ninja...unfortunately, their information is all wrong."
 * Did You Just Punch Out Cthulhu?: Both incarnations of the franchise involve Ryu eventually fighting giant demons.
 * Difficulty by Region: The NES version of Ninja Gaiden III increased the damage sustained from enemies by twice the amount compared to the its Famicom counterpart, while limiting the number of times the player can continue after a Game Over and removing the password system. Moreover, if the player loses a life in the NES version, he will respawn at the beginning of the entire stage instead of the last area he was like in the Famicom version.
 * Do Not Do This Cool Thing: The What Measure Is a Mook? message in Ninja Gaiden 3 is severely undermined by just how glorious it feels to perform the steel-on-bone finishers, all with flashy camera angles, juicy sounds and subtle vibrations. Although the more sensitive players may want to let the mooks live when they are scared shitless after you perform the fire-dragon Ninpo.
 * Doppelganger: The aggressive Doppelganger Fiends in the modern series. They are capable of doing nearly every single one of Ryu's moves and every single advance technique a player must know.
 * The Bio-Noid doppelganger from The Ancient Ship of Doom.
 * The Epigonos from Ninja Gaiden 3, and it comes in two forms: the first has Ryu's form, the second has a fiendish transformation and can switch between 3 weapons like Ryu. It's not as aggressive as the fiend versions and they easily fall for the Izuna Drop, even in harder difficulties.
 * Doppelganger Attack: The Kelbeross beasts from the first two NES games, where only one of them was vulnerable but both were very, very deadly. Similarly, Ryu acquired this skill in The Dark Sword of Chaos, where he could generate up to two Shadow Clones that could not be killed, would follow in his footsteps precisely (even stopping in midair if Ryu himself jumped and then stopped moving), and would slash or use Ninja Arts in perfect sync with him. A great deal of boss strategies centered around proper positioning of these clones while Ryu himself ducked into a safe spot.
 * And let's not forget the Doppelgänger Fiends.
 * Down the Drain: The "aqueduct" chapter in the first Xbox game. A sizeable chunk of the sequel's third chapter also takes place in a sewer.
 * Dual-Wielding: Kitetsu, Dragon's Fang and Tiger's Claw, Falcon's Talon, Tonfa,.
 * The Tonfas were, historically speaking, supposed to be used two at a time. However, they add tungsten tips... and then BLADES on them.
 * Basaquer in the NES games dual-wields butterfly knives.
 * Dual Boss: Curse you, Giants of the Underworld!
 * Also, the "Dragons" pro wrestling duo in the arcade version.
 * Plus, the Tengu brothers in Ninja Gaiden Sigma 2. Although it's an odd example since you alternatively fight them alone and together several times throughout the game (see Recurring Boss below).
 * The Quetzalcoatl in Ninja Gaiden II (360 version only).
 * In the original trilogy, it's the Kelbeross in the first two games, followed by Great Koganei in the third.
 * Earn Your Fun: Itagaki isn't the page quote for nothing.
 * Easy Mode Mockery: In Ninja Gaiden Black, you unlock easy mode if you die too many times on the first level, but not before Ayane admonishes you for being so weak. She then proceeds to give you a purple ribbon powerup, and all the power bracelets become ribbons as well.
 * Elaborate Equals Effective: Used for every weapon in the Xbox games, except for the katanas. And even for katanas if you count the True Dragon Sword and the Blade of the Archfiend replacing Dragon's Claw and Tiger's Fang in Ninja Gaiden II.
 * Eldritch Location: The Realm of Chaos, the Labyrinth of Shadows, and the Ancient Ship of Doom.
 * Elevator Action Sequence: Rachel's chapter in Ninja Gaiden Sigma 2 has one of these.
 * Elite Mooks: The Underworld versions of the Incendiary Shuriken ninja deal much more damage than their normal counterparts who were already cheap enemies, but they also feature a quasi-suicide attack where they stab you in the chest with one of their claws and then detonate an Incendiary Shuriken attached to their impaled-arm to deal massive damage.
 * Empathic Weapon: The Dragon Sword.
 * Epic Flail: Nunchaku, Vigorian Flail and Kusari-Gama. The latter two cross over with Sinister Scythe.
 * Essence Drop: In the first two Xbox games, yellow essence is the currency, blue esence refills health and red essence refills Ninpo. Ninja Gaiden 3 removed that feature, for a better Gameplay and Story Integration.
 * Evil Counterpart: As far as the NES games go, it is explicitly stated that the Dark Sword of Chaos is this to the Dragon Sword, having been forged from the Demon's bones (as opposed to the Dragon's fang).
 * Evil Tower of Ominousness: Both the Tower of Lahja, and later the gate to the Chaos Realm, in The Dark Sword of Chaos.
 * Excuse Plot: Primarily a trait of Itagaki's games, which can both be summed up as "Big Bad attacks the village, Ryu chases Big Bad to his lair and defeats Bigger Bad"; there is little dialogue and the details on the mythology picked up here and there in books or scrolls don't really bring much to the plot itself. Hayashi's games (both Sigmas and Dragon Sword) are a tiny bit more fleshed out. Ninja Gaiden 3, however, is much more plot-driven, going back the tradition of the NES games.
 * Expospeak Gag: In the middle of the "Flying fortress" level in Ninja Gaiden II, the intercom voice suddenly stops being serious for a second.

"After Ryu's victorious duel with Jaquio, Ashtar returned to the bowels of darkness and bided his time. But another evil creature was already on its way as another adventure awaits the unsuspecting Ryu Hayabusa..."
 * Expy: Ninja Gaiden 3 is appropriately seen by some fans as the Devil May Cry 2 of the entire series.
 * Eyepatch of Power: Genshin.
 * The Faceless: in Ninja Gaiden Sigma 2.
 * Faceless Goons: Averted in Ninja Gaiden 3 for a full dollop of What Measure Is a Mook?.
 * Fake Difficulty: The Camera Screws were bad enough in the first Xbox game, but the second added some extremely cheap mooks, always in hordes, who have grabs that are way too fast to anticipate, or ones who constantly spam explosive projectiles, mostly from off-screen. Mentor and Master Ninja Modes often takes this straight into Bullet Hell.
 * Fan Service Pack: Dead or Alive: Dimensions' inclusion of and revealing that, pretty much "upgraded" all of.
 * Faux Action Girl: Irene despite being a badass CIA agent finds herself captured in both the first and second games. Played with both ways in the third game, which begins with Irene being apparently murdered by a Ryu clone during the opening credits while spying on a secret lab. However, she later has a Big Damn Heroes moment when she rescues Ryu from the same clone with a machine gun.
 * In the XBOX version, Rachel, who kills a random Fiend when she's introduced and then spends the rest of the game getting captured, thrown around Vigoor and being strung up for a sacrifice. Lovely outfit, however.
 * This gets fixed in Ninja Gaiden Sigma: Rachel becomes a fully playable character in that edition, and is thusly promoted to full-on Action Girl status.
 * Who still gets constantly captured and thrown around in the cutscenes. Aside from being promoted to a playable character, her role in the story didn't change.
 * Sonia, in Ninja Gaiden II, plays the badass CIA agent a little more convincingly. Whilst she manages to get captured and needs rescuing at the start of the game, she repays the favour by showing up like a Big Damn Heroes and saving Ryu from a battle against impossible odds, and later by strolling around the enemy's flying fortress casually dispatching ninja mooks with a rocket launcher.
 * And then she subsequently gets demoted by getting captured again, put into a dress that is marginally less Stripperific than her regular attire, and fails to do anything useful from that point on (although admittedly, it's kinda hard to do anything if you're not a Badass Ninja.
 * Really, Ninja Gaiden has become a Faux Action Girl factory, since hot, playable female characters have become a selling point, but the main character always remains Ryu, requiring 1-3 seemingly-competent women to still need him bailing them out every game.
 * Fetch Quest: The golden scarabs in the first Xbox game and the crystal skulls in the second. The latter is especially bad: when you collect the 30 hidden skulls, you are rewarded with... a giant crystal skull. That seems to be of no use whatsoever. It might have some sort of effect, but the description of the object is too crytpic to determine what.
 * Field of Blades: In Ninja Gaiden II, the last part of the infamous Chapter 11.
 * Fighting with Chucks: Ryu can pîck up and use nunchucks. The Vigooran Flail is a bladed pair of nunchucks, and it's as awesome as it sounds.
 * Finishing Move: Obliteration Techniques, Fiend Sealer and variants
 * Flash Step: Several charge attacks emulate this. Most ultimate attacks in the second game rely on this to continue the attack. The True Dragon Sword's ultimate attack upgrades this into outright Teleport Spam.
 * Flunky Boss: Masakado and Marbus in the first Xbox game; Zedonius and Dagra Dai, as well as the second fights against Rasetsu, Genshin and Volf in Ninja Gaiden II. And in Ninja Gaiden Black, Ninja Gaiden Sigma and Ninja Gaiden II, every single boss turns into this in higher difficulties.
 * For Massive Damage: In Ninja Gaiden Sigma 2, the Tonfa's Ultimate Technique is devastating, more than those of any other weapon. Even the extremely resilient Underworld clawed Ninjas of Ninja Gaiden Sigma 2's Master Ninja mode fall apart instantly with only a half-charged UT. It's surprising since apart from that the Tonfa are arguably the weakest weapon of the game… Then in the first Xbox game, there is the Unlaboured Flawlessness on low health, capable of near One-Combo Kills on the weaker bosses (see for yourself).
 * Four Is Death: The Malice Four in the first NES game.
 * Frickin' Laser Beams: Paz Zuu's laser, oddly enough, doesn't damage you directly; instead, it traces a path, which ignites shortly afterwards.
 * Unfortunately, the black pincer fiends aren't so kind-hearted with their own eye-beam. Which has infuriated more than one player.
 * Gameplay and Story Integration: Ninja Gaiden 3 makes a point of eliminating elements that "break the immersion" apparently. No Hyperspace Arsenal, no statues that teleport you to a shop, no healing items, no orbs coming out of dead enemies, and the save point statues are replaced by a hawk following Ryu.
 * Giant Space Flea From Nowhere: The ankylosaurus at the end of Ninja Gaiden II Chapter 7 would seem to fit, but it's actually seen and referred to at least once before you fight it. The two you eventually face in the Underworld, however, fit this trope.
 * And really, a good portion of the minibosses fit this as well. The Rasetsumaru-class ninja show up in the oddest of places...
 * The most egregious example in Ninja Gaiden II is the metallic horned centipede… thing at the end of Chapter 3.
 * Gratuitous Japanese: The original Japanese version was titled Ninja Ryûkenden (Ninja Dragon Sword Story), so the English version's title almost makes it seem like a Gaiden Game when it isn't at all.
 * Grenade Launcher: Some mooks have these in the first Xbox game, and Ninja Gaiden Black gave the tanks these to counter an easy means of defeating them, which was to get so close that it could only circle without being able to fire its main gun, only a mounted machine gun with a suppressable gunner.
 * Guns Akimbo: Gamov is essentially a Mysterious Watcher throughout the game and even outlives his usefulness at the end, but when you fight him as a boss in Ninja Gaiden Sigma, he turns out to be a Gunslinger who is also very capable in close combat. He may not be the hardest boss of the game, but not the easiest either.
 * Happily Married: Ryu and Irene after the NES trilogy, during the OVA and carried over to the Dead or Alive series, until this fact was stopped being mentioned in the latter after Itagaki envisioned the modern trilogy, possibly in an attempt to discard the idea of his creation being a long Prequel for the original NES trilogy, turning into a new continuity altogether, and leaving Ryu free for new interests. It took Dead or Alive: Dimensions to fix the timeline again, namely bringing Irene back to make things stable... although the game is still very vague on the romance/marriage matter.
 * Harder Than Hard: Very Hard/Path of the Mentor and Master Ninja/Path of the Master Ninja.
 * Ninja Gaiden II (Xbox) was this on any difficulty... for questionable reasons.
 * Players who became proficient on Path of Acolyte/Warrior would end up dying in the first battle of Path of the Mentor. All enemies are upgraded to those you previously encounter later on and you start out with no upgrades.
 * Heads I Win, Tails You Lose: The first fight against the Regent of the Mask in Ninja Gaiden 3. You stab him for what seems to be the finishing blow... but instead, he grabs Ryu's sword and fuses it into his arm, giving him a Red Right Hand for the rest of the game.
 * Heel Face Turn: Awakened Alma saving Rachel.
 * Hell Gate: Mt. Fuji is one, apparently. The NES game The Dark Sword of Chaos presents a recursive example: an evil-looking tower with a demonic skull for an entrance, which leads to the antechamber of the Realm of Chaos. And inside that, an altar upon which the actual gates can be opened.
 * Hell Hound: The Kerbeross beasts from the NES Ninja Gaiden I and Ninja Gaiden II.
 * Heroes Want Redheads: Irene Lew is a redhead in the original trilogy. As Sonia, her hair (supposedly bleached) is blonde.
 * Heroic Sacrifice: Awakened Alma saving Rachel, as said above.
 * And in The Dark Sword of Chaos, not only is it heavily implied that Robert died while Holding The Line to protect Ryu's back, but the Dragon Sword itself makes a sacrifice to revive Irene at the end.
 * High-Pressure Blood: While Ninja Gaiden II went for the Ludicrous Gibs option, Ninja Gaiden 3 took the High-Pressure Blood one.
 * Highly-Visible Ninja: Who said ninja games need a stealth mechanic?
 * Sadly, there's the one time in Xbox Ninja Gaiden II where they make it seem like you could be stealthy for once..... It gets retracted in about three seconds. How fast can you replace a searchlight that seemingly exploded for no reason?
 * However, Ninja Gaiden 3 introduces stealth kills, although they are totally optional.
 * Hopeless Boss Fight : There are two in Ninja Gaiden Sigma. In Chapter 2 against, when you have only a level 1 Dragon Sword and a rachitic lifebar. And in Chapter 14 with Rachel when you fight . In both cases, a normal player will likely get his ass handed to him before understanding what's going on. It is technically possible to win those fights, but that requires insane skill, and even if you do, your character gets beaten in the cutscene anyway.
 * How We Got Here: Ninja Gaiden 3 begins with the scene of the very first trailer of the game: a "second person" perspective of Ryu coldly assassinating an enemy and removing his mask, with chaos in the background. Then you start fighting a giant humanoid monster… before the title appears and the story flashes back to Day 1..
 * Hyperspace Arsenal
 * Idiosyncratic Difficulty Levels: In Ninja Gaiden II, the difficulty runs Acolyte, Warrior, Mentor, Master Ninja... and, of course, Master Ninja came from the Ninja Gaiden Black version of the Xbox series' first game.
 * I Have the High Ground
 * "I Know You're in There Somewhere" Fight: Ryu versus his brainwashed father in the first NES game.
 * I Let You Win: Murai.
 * Immune to Bullets: Many higher-level enemies in the Xbox games are immune to standard shuriken or can block them if you throw them off-the-cuff instead of as part of a combo. In the weapon description of Rachel's sidearm in Ninja Gaiden Sigma 2, it states outright that high-level fiends are immune to her magic-laden ammunition, crafted specifically to give her an edge in fighting the damned things in the first place.
 * Imperial Stormtrooper Marksmanship Academy: Averted hard in the modern games. Gun-toting enemies are very competent at aiming and can be a real hindrance. The only exceptions are the basic hooded mooks of Ninja Gaiden 3, who consistently shoot over your head, even when you're kunai-climbing a wall and you are not 3 meters from them.
 * Impossibly Cool Weapon: The Vigoorian Flail is solidified awesomeness, but in Real Life, it would be more dangerous for the user than for the target. And it probably wouldn't swing as easily a nunchaku either. Then there is the Plasma Saber Mk. II. Most projectiles are also this: the Incendiary Kunai, the Fuuma Shuriken, the Gatling Spear Gun and Ninja Gaiden Sigma 2's Howling Canon.
 * Infinite Supplies: Ryu has an endless supply of standard shuriken. Also, enemies with small arms have to periodically reload (it's most evident with the MSAT), but they never run out of magazines.
 * In Ninja Gaiden Sigma 2, he also has an infinite amount of arrows. In the first game and Ninja Gaiden II, there is a limit, but there will always be a body bristling with arrows nearby when you need it.
 * Instant Death Radius: The Xbox games have the Gleaming Blade move and its Ultimate Technique versions, which eat Mooks for breakfast.
 * Interquel: Ninja Gaiden III: The Ancient Ship of Doom takes place after the events of the first NES game, but before the events of Ninja Gaiden II: The Dark Sword of Chaos, which is why Ryu is still in possession of the Dragon Sword despite having lost it at the end of Ninja Gaiden II. The Japanese manual makes the game's setting clear, but the American manual only implies it subtly.


 * Same deal with Ninja Gaiden: Dragon Sword for the Nintendo DS, it happens after Ninja Gaiden (Xbox), but before Ninja Gaiden II (Xbox 360); you can tell it definitely happens after the first Xbox game, but looking at how the original Ninja Gaiden II for Xbox 360 handled its storyline, there was no way to tell its place after Dragon Sword without looking for information outside the game's material, it was only made clear that Dragon Sword happened before the original Ninja Gaiden II, in Ninja Gaiden Sigma 2 for PS3 with the inclusion of Momiji and Sanji in the game.
 * Invulnerable Attack: Ninpo, off-the-wall attacks, throws, Obliterations and Ultimate Techniques in the Xbox games (plus some spin attacks in Ninja Gaiden II). In the higher difficulties of Ninja Gaiden II, knowing how and when to use these is actually crucial.
 * Jiggle Physics: Itagaki is very fond of this trope in his games. Ninja Gaiden Sigma 2 gives us the ability to control this with Sixaxis motion sensing…
 * Jump Physics: Remember, kids: you can change directions and accelerate multiple times while mid-air, and maintain yourself in the air by maiming an enemy!
 * Kaizo Trap: The giant armadillo boss in Ninja Gaiden II for Xbox explodes after death, which kills you instantly. The only way to avoid death is to hold the block button, which is rather counter-intuitive since no other explosive attack in the Xbox series can be blocked.
 * Fiend-Sealer Them While They Are Down: Also at least two of Ryu's Obliterations involve brutally kicking them in the face before delivering a vicious dismembering...
 * Large Ham: Volf, all the way.
 * The Regent of the Mask in Ninja Gaiden 3 takes his share too.
 * Ledge Bats: The birds.
 * The Legions of Hell: What will pour out of the Gate of Darkness to the Realm of Chaos if Ashtar's ritual is completed. Many foes in the games already hail from there.
 * Le Parkour
 * Life Drain: A special ability of Kitetsu, Doku's demonic sword in the first Xbox game. You can do it to minor mooks the same way Doku does it to you... and regain quite a bit of health that way. However, the rest of the time you use it, the blade drains your own health. In Ninja Gaiden Sigma (PS3), holding the sword doesn't deplete your lifebar, but the effect of the Life Drain attack is also considerably nerfed.
 * The Alchemist enemies in Ninja Gaiden 3 also have a grab move like this.
 * Lighter and Softer: Ninja Gaiden Sigma 2 is this compared to the second Xbox game, graphically speaking. Most of the blood and gore is removed, and it uses noticeably brighter color tones and a bloom effect.
 * Living Statue: In Ninja Gaiden Sigma 2, you fight a giant Buddha statue as a Warmup Boss, and a few chapters later the freaking Statue of Liberty.
 * Lock and Load Montage: Cutscene between Chapters 2 and 3 in the Xbox version where Ryu is shown tightening the straps on his outfit and bringing three kunai with him while Murai chatters in the background.
 * Losing Your Head: Inverted with the zombies in the first two Xbox games, that continue their attacks even after being decapitated... although if they are they become blind and just smash randomly. The flare fiends in Ninja Gaiden Sigma 2 can also fight headless, and they are not blinded.
 * Lost Technology: Twin Serpents Plaza statue.
 * Love At First Sight: Both Ryu and Irene in the first NES game, after an entire adventure without any proper build up for romance. In fairness, Ryu took the fact he was able to meet her as a fitting payment for all the trouble they went through, and Irene seems to have the same mindset on this matter as she disregarded Foster's direct orders to kill him. The result is the couple kissing at the end; as of Dead or Alive, they are Happily Married and running their Antique Shop together.
 * Ludicrous Gibs: Every weapon in Ninja Gaiden II can dismember and dice opponents, not that this deters them from fighting. Werewolf enemies will even pick up stray body parts and throw them at you.
 * Macross Missile Massacre: Thanks to some BFG toting ninjas in the later levels of Ninja Gaiden II, you get to be on the receiving end of these.
 * Magikarp Power: Xbox's Wooden Sword is pathetic until the final upgrade level, where it becomes the Unlabo(u)red Flawlessness, a Game Breaker for those skilled enough to use it.
 * The Man Behind the Man: Doku -> Vigoorian Emperor ->.
 * Original version: Jacquio --> Ashtar --> Jacquio. Trust me, it makes sense in context.
 * Marathon Level: Many in the first Xbox game, notably those with long puzzles. In Ninja Gaiden II, nearly every single chapter is this, but Chapters 6, 8 and 11 are the most notable. Especially the latter.
 * Mask Power: Inverted with the Ogres from the Xbox remake, who grow stronger after Ryu breaks their masks.
 * Ashtar from The Dark Sword of Chaos wears a smooth, faceless metal mask with only thin slits for the eyes... or maybe the eyes are part of the mask.
 * Mega Corp: Lords Of Alchemy in Ninja Gaiden 3.
 * Mercy Kill: One of the developers of Ninja Gaiden II described the obliteration techniques as this.
 * Mercy Mode: Ninja Dog in the first Xbox game, Hero mode in Ninja Gaiden 3.
 * Mighty Glacier/Stone Wall: The purple zombies of the first Xbox game. They carry enormous bayonet guns, their attacks are pretty damaging, but they are so slow, you have to be really careless to get killed. And they just never go down. It takes three full Ultimate Techniques of the low health Unlaboured Flawlessness to make them bite the dust... meaning they have more health than some bosses.
 * Mook Bouncer: The black laser fiends in the first Xbox game are already very annoying in themselves. But in the tower section of the last but one chapter, they can use a really nasty grab move that drags you underground and sends you back at the level below, forcing you to go through the previous wave of enemies again and through a wave of ghost fish. Even more infuriating if you are doing a Karma run since it prevents you from getting any more points in that fight (it's counted as if you had fled the fight).
 * Mook Chivalry: Chivalwhat?
 * Mook Debut Cutscene: Generally averted in the Xbox games, with a few exceptions like the MSATs, the Zombies and the flare fiends in Ninja Gaiden I, or the Van Gelfs in Ninja Gaiden II. Although in both cases, the "rank" of the enemy introduced will actually change depending on the difficulty: for example, a purple (immature) Van Gelf will come out of the hole in Accolyte, a green one (winged) in Warrior, and a golden one (the strongest type) in Mentor.
 * Most Definitely Not a Villain: Murai starts off the first Xbox/PS3 game by sending dozens of his men at you to be killed. Then he sends you a letter encouraging you kill as many people as you can, including civilians because their blood will make the Dark Dragon Blade stronger. Yeah, good luck guessing who the "surprise" final boss will be.
 * Multi Mook Melee: The so-called fiend challenges in Ninja Gaiden I and Ninja Gaiden Sigma, and the Tests of Valor in Ninja Gaiden II, removed in Ninja Gaiden Sigma 2. Ninja Gaiden II/Ninja Gaiden Sigma 2 also has the famous stairway fight in Chapter 10/13, where you face a ridiculous number of enemies at the same time and take down a good hundred of them. Hell, in Ninja Gaiden II's Master Ninja mode, the game is pretty much a 12 hour long Multi Mook Melee!
 * Multiple Choice Past: It all comes down to TECMO simply establishing an official timeline without producers stating their own versions, until is made clear what game represents Ryu's true first known adventure: be either the arcade game, the NES series or the Xbox series; as of now, Ryu Hayabusa and the world around him does not have a consistent past, and the timeline itself for that matter.
 * Mysterious Watcher: Ayane and Gamov from the Xbox title.
 * Nerf: The Flying Swallow in the first version of Ninja Gaiden on Xbox was toned down in the re-release Ninja Gaiden Black because you could spam it on pretty much everything with success. Ninja Gaiden Black featured enemies that were specifically designed to punish you for using it (i.e. block the attack entirely and counter it). You definitely did not want to be caught using that on the advanced MSAT soldiers.
 * The Spin Attack from the first NES game was removed from the sequels. The Invincible Fire Wheel, an equippable (albeit expensive) Ninja Art was turned into a limited, single-use powerup for the third game.
 * The Fire Wheel is further nerfed for the Xbox remake compared to the NES days. It creates a flaming shield around Ryu, but it knocks away most enemies on contact which severely limits its usefulness (continuous damage is impossible, and it knocks them out of your melee weapon's effective range). You are also far from invincible.
 * The explosive kunais used by Ryu in Ninja Gaiden II systematically dismembered the enemy the first time and killed the second. In Ninja Gaiden Sigma 2, those used by Ayane are quite effective in normal mode, but are about as useful as shuriken in higher difficulties. Ninja Gaiden Sigma 2 also removes the ability to charge arrows. Then again, in both cases, the limit in supplies has also been removed, so keeping these projectiles as powerful would have turned them into Game Breakers.
 * Ninja Gaiden 3 indirectly nerfed the Izuna Drop: it is still an instant kill move, but tougher human-sized enemies have be weakened before you can lift them up, so it is not quite as game-breaking as in Ninja Gaiden II.
 * New Game+: Used in the second Xbox game. Ninja Gaiden Sigma 2 suverts this a bit with Chapter Challenge mode: once you beat a difficulty, you can redo the chapters individally with all your weapons and ninpo upgraded (not unlike Devil May Cry). So it's not technically a New Game+, but functions as one, except your life bar's length depends on the chapter you play. The game is also slightly more difficult in that mode.
 * Nice Job Breaking It, Hero: A minor example in next-gen Ninja Gaiden II (minor in that Ryu fixes it pretty fast)..
 * The NES games were fond of this. In the first one, . Then a year later,.
 * Ninja
 * Ninja Pirate Zombie Robot: Funky Dynamite, a man-sized mutant lizard cyborg with a jetpack and plasma guns.
 * Nintendo Hard: And the guys at Team Ninja know it. You get an achievement for continuing enough times!
 * And the XBox games are actually easier than the older 8-bit games, which range from "Brutal" to "Devour your controller in frustration" in difficulty.
 * Non Dubbed Grunts: Dragon Sword has no English voice track, as Tecmo Toei felt no need to hire English voice actors, since the game only has grunts and a few words uttered through the whole adventure. Still, it's quite impressive that all sounds and grunts alike are performed by the original Japanese voice actors, and actually recorded for production, not recycled tracks from the console versions.
 * Nonstandard Game Over: You can actually shoot Sonia dead near the end of Ninja Gaiden II. The proportion of players who didn't try at least once is 0%.
 * No Pronunciation Guide: A lot of people tend to mispronounce the title as "Ninja Gay Den" (rather than "Ninja Guy Den").
 * Lampshaded in both the Ninja Gaiden episode of The Angry Video Game Nerd and its Hilarious Outtakes, when the ninja thinks of calling it "Ninja Homosexual-den" in one scene.
 * Norio Wakamoto: Robert T. Sturgeon, the Special Forces operative who aids Ryu throughout Ninja Gaiden II: The Dark Sword of Chaos, gets blessed with Wakamoto's voice in the OVA.
 * As well as Ryu's father in the modern series.
 * No Sidepaths, No Exploration, No Freedom: In the first Xbox game, you can still explore a bit or find a few secret paths, as well as stroll in previously visited areas; this is helped by the fact that 90% of the game takes place inside or near the same city. The second and third game, however, are much more linear. Especially the third, where there are no items to pick up, so any semblance of exploration has vanished.
 * Numerical Hard: In the original Xbox game, the difference between Normal and Hard was barely noticeable; there were more, slightly tougher enemies, but that was pretty much it. Like so many other things, Ninja Gaiden Black and Ninja Gaiden Sigma corrected this by replacing basic mooks with new, much tougher ones, and turning every boss into a Flunky Boss.
 * Obstructive Foreground: Used in the second NES game intentionally, with infuriating results.
 * Obvious Beta: The Mega Drive version. Subverted because it was never actually released at all. How it got leaked through the internet has never been completely clear.
 * Omnicidal Maniac: The Dark Dragon in the DS game, according to Nicchae, would have annihilated both humans AND Fiends had Ryu not destroyed it soon after its birth.
 * Once Per Episode: In the modern series, the first three game have the Hayabusa village attacked at the beginning: by Doku in the first, by the Black Spider clan in Dragon Sword and Ninja Gaiden II.
 * One-Hit Kill: Master Ninja mode's ungodly difficulty in Ninja Gaiden Sigma 2 relies on the fact that the player has very little room for mistake. Several enemy attacks like fire geysers, and any boss grab or suicide attack will kill you instantly regardless of your lifebar's length.
 * One-Man Army
 * One-Time Dungeon: In the first Xbox title, you can't go back to the Ninja fortress of Chapter 1 nor in Chapter 3's airship since it crashes.
 * One-Winged Angel: For the Xbox title: Alma -> Awakened Alma, Doku -> Spirit Doku, Vigoorian Emperor forms one and two. And the final boss in the sequel.
 * In the original version, Jacquio in the first two games and Clancy in the third.
 * Only a Flesh Wound: Game mechanic in Ninja Gaiden II for Xbox 360: enemies act differently depending on how they've been dismembered.
 * And in some ways, they become even more dangerous when they've lost a limb; they do grab/suicide attacks that are very hard to avoid and heavily damaging.
 * Only Idiots May Pass: Subverted in the remake.
 * Painfully-Slow Projectile: Averted in Ninja Gaiden II: white ninja archers fire explosive arrows that are so fast, you can't possibly dodge them in time. They are unblockable. They can hit you underwater. Oh, and in Master Ninja mode, you will fight them right at the beginning, waiting for you across gaps or targetting you while you're running on water. Everyone's got their four-leaf clovers?
 * Played straight in the NES trilogy, thank goodness. The Platform Hell aspect of the game is hard enough as is; it's almost Nightmare Fuel to think of what it would be like had the several enemies who shot at you or threw shuriken at you did so quickly.
 * Platform Hell: The NES series. If it wasn't bad enough that Tecmo forced you to use the wall cling ability and jump across tiny platforms over pits, but they decided to throw in the Goddamn Bats, eagles and even the grunts on full force. And in the first two games, they respawned infinitely.
 * Playing with Fire: Most of Ryu's Ninja Arts in the NES trilogy revolve around flinging fireballs... or encasing yourself in them with the Invincible Fire Wheel.
 * Then you get Art of the Inferno, Fire Wheel, and Phoenix in the Xbox titles.
 * Pivotal Boss: The spider tank in Ninja Gaiden 3 is more or less this, although it can attack you even without facing you directly.
 * Power Glows: After you upgrade to the True Dragon Sword, it gains a purple aura.
 * Also in Ninja Gaiden 3, your weapon or your right arm glowing red indicates when you can unleash an ultimate technique.
 * Precision-Guided Boomerang: The Windmill Throwing Star in the NES games.
 * Press X to Not Die: One of the most frequent complaints regarding Ninja Gaiden 3 is the heavy use of scripted sequences... of the "you can take a shower and have a tea before pressing the button" type.
 * Prequel: The X-Box games and the DS Game Dragon Sword compared to the NES originals.
 * Pretty in Mink: Ayane's alternate costume in Ninja Gaiden Sigma 2.
 * Product Placement: Ninja Gaiden II has some in the New York level, notably for Toshiba. Strangely, you don't see them in Ninja Gaiden Sigma 2.
 * A Protagonist Is Ryu
 * Punch Clock Villain: Arguably the Special Forces and Vigoorian Military, though the journals found in Ninja Gaiden II show the Black Spider ninjas to be something of this as well.
 * Race Against the Clock: In Act 7 of Ninja Gaiden III: The Ancient Ship of Doom, should you make it to the Final Boss without dying, you will notice that the timer is very close to zero once you reach Clancy.
 * Recurring Boss: Genshin.
 * The Tengu Brothers in Ninja Gaiden Sigma 2: first, you fight one alone early in Chapter 5, who flees in the middle. You fight them together at the end of the same chapter. Then in the beginning of Chapter 14, you fight the two but one of them escapes in the middle. You kill the other, and the one that escaped reappears at the end of the chapter, with a few other ninjas. And finally, you fight the two in Chapter 16. What's interesting is that you almost always have to fight them after going through several long and harsh fights, with no possibility to save between the fights, meaning you will rarely confront them at full health.
 * The Regent of the Mask in Ninja Gaiden 3.
 * Red Right Hand: In the third game,.
 * Refuge in Audacity: The boob-jiggling feature in Ninja Gaiden Sigma 2. You can even do it during cutscenes.
 * Reports of My Death Were Greatly Exaggerated: In The Ancient Ship of Doom, Irene is supposedly killed by Ryu's doppelganger on Foster's orders. In truth, she had faked her death and was working with the U.S. Army to uncover evidence on Foster's crimes.
 * Respawning Enemies: Yup. And often you'll hate it.
 * Retcon: Some worth of mention, Tecmo passed the series around to just about any willing developer and producer: Natsume, Team Ninja, Tomonobu Itagaki, Yosuke Hayashi, etc. Of course, they had their own visions for the series:
 * Ninja Gaiden Shadow for Game Boy is said to be set three years before the NES series.
 * The fact Ryu Hayabusa is in his early 20's in the NES series don't match up with the Xbox series either. This is the major factor why Flip-Flop of God is heavy in regard the Xbox series being a Prequel to the NES one. NES Ryu from 20 to 23 ventured through the trilogy and settled in the Dead or Alive series just as Xbox Ryu from 21 to 22 ventured trough the present series and settled in Dead or Alive series at 23 years old. The only way to reconcile this is saying that Ryu has ventured through the NES and Xbox series for about the same time.
 * Irene Lew became a walking Retcon herself when Sonia was revealed to be just another one of her codenames she uses on the field as of Dead or Alive. Now it seems that Ryu actually knew Irene before the NES series in Ninja Gaiden II (Xbox 360), while in the first NES game, he certainly doesn't find Sea Swallow familiar to a certain Sonia he met before. Also Irene's appearance of course was always that of a blond buxom babe with pale skin instead of a brunette with modest body proportions; maybe she was wearing a disguise in the NES series?
 * Ryu and Irene's marital status. The first Dead or Alive game says that they are Happily Married, and Irene dutifully runs their Antique Shop while Ryu is away fighting in the tournament. In the very next Dead or Alive game, their marriage became a mysterious subject: Ryu still is an Antique Shop owner, but Irene is not mentioned in his bio anymore; in fact, it was doubtful that Irene even existed from the 2nd tournament (game) to the 4th tournament. When Dead or Alive: Dimensions was released, it recaps the first four tournaments and brought her back into the fray, but the marriage remains a mystery, and suddenly, Irene's a CIA agent again. The recap of Dead or Alive: Dimensions just goes as far as to imply they're romantically involved.
 * Joe/Ken Hayabusa's whereabouts. Ryu's father dies in the NES trilogy, yet he's alive and kicking in the modern series, which is totally fine since it's a Prequel series. Then comes Dead or Alive and make things difficult, as the first game makes no mention of Joe at all; it doesn't even touch upon the Hayabusa Clan either. It only shows that Ryu is taking the position of clan leader for the moment and doesn't say anything else since his father was always fond of leaving his son to taking care of the clan while he spent seasons training on top of the mountains.
 * Retired Badass: Muramasa, the doddering old shopkeeper, makes carving up ninjas look effortless.
 * Which makes it quite hilarious when he says just after that that his old legs won't allow him to go at the top of Mount Fuji. This is dubious since he apparently managed to build statues of himself in the Underworld…
 * Revival: NES -> Xbox.
 * Also counts as a Video Game 3D Leap.
 * Roaring Rampage of Revenge
 * Rock Beats Laser: Vigoorian forces, meet Dragon Sword! Dragon Sword! Meet! Vigoorian forces! Also subverted against the tanks and helicopter, which Ryu needs to use modern arrows to beat.
 * Partially subverted at least. The bow is really outdated since everyone else has at least a machine gun at that point in the game. What sensible person/army would use resources to make special armor piercing/explosive arrows for a weapon as outdated as the bow? Especially since the enemies gain increasingly large caliber guns as the game progresses.
 * Throughout The Ancient Ship of Doom, instead of heading into a hellish dimension to battle demonic creatures like in the first two NES games, Ryu faces a high-tech robotic army at (mostly) artificial environments, culminating with a battle within an alien ship against a laser-equipped giant mecha.
 * Role Reprisal: English-wise, Kasumi is once again voiced by her Dead or Alive 5 voice actress Lauren Landa. Averted with Ayane, who retains Janice Kawaye from Ninja Gaiden II.
 * RPG Elements: In Ninja Gaiden 3's mission and online modes, you start up as a newbie Ninja and have to complete trials to level up and improve your combos and equipment. This is quite surprising, as the story mode of the same game removed everything that remotely looked like an upgrade system.
 * Rule of Cool: The entire Xbox series in general thrives on this.
 * Rule of Three: In the original trilogy, Ryu has to fight three bosses in succession.
 * Ryu Hayabusa Is About To Stab You: The cover of the NES Ninja Gaiden III: The Ancient Ship of Doom shows Ryu pointing his sword at the viewer. The first and second games in the NES trilogy are less aggressive, showing him holding a kunai towards the viewer or unsheathing a sword at the viewer. The Xbox covers give him much more relaxed, almost casual poses.
 * Say My Name: In the second NES game, multiple times.
 * Scenery Porn: Some of the levels in Ninja Gaiden II are gorgeous. Special mention for the level taking place atop the Tokyo skyscrapers.
 * The game also has one of the more beautiful game portrayal's of central Moscow (albeit the city is never named), going through Red Square, the GUM, the Underground, some nearby churches and buildings, before ending in Spaskaya Tower. St. Basil's Cathedral is absent.
 * The NES series had a fair amount of this as well: each game had at least one cutscene that was just a grand panoramic sweep that generally showed a very small Ryu in the foreground gazing upon his uniformly majestic destination, and many of the backgrounds and stages were more visually detailed and attractive than the player was likely to notice.
 * Schmuck Bait: The Demon Statues from the first NES title.
 * Self-Imposed Challenge
 * Sequel Difficulty Spike: Rather "rerelease difficulty spike": the original Xbox game was hard but nothing scream inducing. The Updated Rerelease Ninja Gaiden Black (and by extension Ninja Gaiden Sigma) cranked the difficulty up a couple notches by introducing new vicious enemies, giving the existent ones a better AI (and a grab move for Black Spider Ninjas), throwing out the window what little Mook Chivalry they could have, significantly nerfing overly efficient moves like the Counter or the Flying Swallow, and adding the utterly sadistic Master Ninja Mode.
 * Ninja Gaiden II is also infamous for being this, but not always in a good way.
 * Sequel Escalation: Between the two Xbox/PS3 games. Ninja Gaiden Black/Ninja Gaiden Sigma sure is Nintendo Hard, but it is moderately gore, has a relatively slow pace, you never fight more than three or four enemies at once, and the strongest moves are restricted in use. Ninja Gaiden II takes the gore to ridiculous levels, is much faster, much more offensive, you frequently fight insane numbers, and the special moves, combos and weapons are cranked up to the point they would have been absolute Game Breakers in the first game. Ninja Gaiden Sigma 2 toned down the gore and number of enemies though.
 * Sequential Boss: All three NES titles, plus Vigoorian Emperor in Xbox. Most bosses in Ninja Gaiden 3 are also like this (which may explain why they have no life-bar).
 * Serial Escalation : Ninja Gaiden Sigma 2 has a team mission mode with five levels: Acolyte, Warrior, Mentor, Mater Ninja... and Ultimate Ninja. The latter has missions that make even the most experienced players have a Heroic BSOD the first time. Like fighting the four Greater Fiends simultaneously. You won't be able to do anything in those missions without an experienced human partner.
 * Shoulders of Doom: Ashtar rocks an impressive set of shoulderpads.
 * Shout-Out: In the New York level of Ninja Gaiden II, you can see some scrolling signs reading "Doatec". Since the two series take place in the same universe, it makes some sense.
 * Single-Stroke Battle: The opening cutscene of NES Ninja Gaiden, where Ryu's father gets defeated via this. Of course, he later ...
 * The attract cinematic of the arcade version features a similar battle between the main character and a random mook. Never bring brass knuckles to a sword fight...
 * Sinister Scythe: The Vigoorian Flails from the Xbox title are essentially nunchucks with scythes on them, which return in the sequel. As well as the Eclipse Scythe and kusarigama in its sequel.
 * Sleeves Are for Wimps: Ryu's arms are the only skin he bares.
 * And his feet, in the "Level Start!" graphic of the first NES game.
 * Robert T. Sturgeon is a devoted follower of this philosophy.
 * Slice-and-Dice Swordsmanship: Both used and averted depending on which move you make Ryu do in the Xbox series.
 * Smash Mook: Ogres from the Xbox remake.
 * Smoke Out: Smoke bombs are used by both Ryu and enemy ninjas in the Xbox series.
 * Spam Attack: Most of the Ultimate Techniques.
 * Spin Attack: Ryu's movelist with the Dragon's Claw/Tiger's Fang consists of some hard cuts and a lot of spinning. Most other weapons also have a 360 degree input that usually turns out to be a spin attack.
 * And the original NES game had the Jump and Slash Technique, a powerful art which turned Ryu into a flying buzzsaw and had the potential to take out Bosses with one good hit.
 * Spinning Piledriver: Ryu is probably the most iconic user of this move in modern action games. Aside from the Izuna Drop, Ninja Gaiden II adds two variants: the Blade of the Archfiend's Underworld Drop and the Tonfa's Flower Garland Drop.
 * Squishy Wizard: In the Xbox games, the mages have annoying and potentially very damaging distance attacks, but are the weakest human enemies in terms of health. Of course, they are only squishy compared to the other Ninja, but still.
 * Completely averted in Ninja Gaiden 3: the Alchemists are among the toughest enemies of the game, especially the white-clad variant.
 * Stealth Pun: This one's a bit of a stretch, but... "Florentine" is both an Italian identity (via its city) and a term used for dual wielding. In Ninja Gaiden Sigma 2, Ryu receives the dual katanas in the Venice based chapter (a city in Italy).
 * Stripperiffic: Rachel's outfit. Enough said.
 * Sonia's outfit in the sequel is just as much, if not more so... to the extent where the diaphanous gown-and-lingerie ensemble she ends up in at the end of the game is probably less revealing.
 * Sunglasses at Night: But Robert is badass enough to make 'em work.
 * Suspiciously Similar Substitute: Sonia, a CIA agent tasked to work with Ryu, who frequently straddles between Action Girl and Faux Action Girl to Damsel in Distress status in the new series replaces Irene Lew, a CIA agent tasked to work with Ryu, who frequently straddles between Action Girl and Faux Action Girl to Distressed Damsel status in the classic series. In fact, they were so similar that eventually in Dead or Alive: Dimensions,.
 * Swipe Your Blade Off: Done by Ryu with all of his weapons in Ninja Gaiden II. Great, more blood to clean up.
 * Sword Beam: The Dark Sword of Chaos can shoot off what looks like ball lightning.
 * Sword of Plot Advancement: Getting the Eye of the Dragon to upgrade the Dragon Sword to the True Dragon Sword.
 * Taking You with Me: A good deal of the crippled enemies in Ninja Gaiden II.
 * Team Pet: The Kelbeross are a villainous example, being Jaquio's pet dogs (well, they were before he mutated them into gargantuan monstrosities). This only gets described in the manual though, leading people who didn't read said manual to consider them a Giant Space Flea From Nowhere.
 * Teased with Awesome: The Blade of the Archfiend at the end of Ninja Gaiden II: since you get it at a point when only bosses and large enemies remain, you can only use the Underworld Drop (the most powerful combo of the game) in the New Game+.
 * Teleport Spam: Some of Ryu's Ultimate Techniques gained this in the shift between the first and second Xbox franchise titles.
 * Ten-Minute Retirement: While some elements of the OVA became Canon Immigrant for the Dead or Alive series (and by proxy the Xbox series), the fact Irene Lew retired from being a CIA agent to run an Antique Shop with Ryu didn't stick, in the Retool of the Dead or Alive series as of Dimensions, Irene can be seen acting as Mission Control for Ryu during his mission, it's unclear if she still is involved with their Antique Shop.
 * There Is No Kill Like Overkill: The combo system allows Ryu to keep mangling decapitated/delimbed enemies.
 * Thriving Ghost Town: Tairon, capital of the Vigoor Empire, doesn't seem to have anyone other than a lone shopkeeper and a bunch of military personnel.
 * Subverted when there are people in the nightclub, but they all run screaming when a giant dinosaur-fiend shows up. That, and the Vigoorian military imposes a curfew more or less as soon as Ryu shows up.
 * Total Eclipse of the Plot: In the first game, the demon is summoned when "the Black Moon rises", meaning a total lunar eclipse.
 * Trailers Always Spoil: Ryu doesn't learn Agent Sea Swallow's real name until the very end of the first NES game. However, the manual already spoils this fact.
 * Trap Door: Ryu's constant nemesis in the NES games. Seriously: Worst. Ninja. Ever.
 * Trick Arrow: Lightly used: Explosive and Armour-Piercing varieties.
 * Turns Red: The Armadillo bosses in Ninja Gaiden II turn red and glow when their health is low, becoming somewhat more dangerous. When finally killed, they explode. Also, Ogres and Berserkers in Ninja Gaiden Black.
 * Unexpected Gameplay Change: The Emperor in the first Xbox game is fought on a floating platform that you must move back and forth (default) or up and down (by holding the guard button) to avoid its Beam Spam. It's painfully unintuitive and tedious.
 * Updated Rerelease: Every modern game had at least one.
 * For the Xbox Ninja Gaiden, there's Ninja Gaiden Black, Ninja Gaiden Sigma (PS3) and Ninja Gaiden Sigma Plus (PlayStation Vita).
 * For Ninja Gaiden II (Xbox 360), there is Ninja Gaiden Sigma 2 (PS3) and Ninja Gaiden Sigma 2 Plus (Vita).
 * Ninja Gaiden Sigma 2's case is a bit special though. Due to an exclusivity contract with Microsoft, Ninja Gaiden II could not be ported onto the PS3. The only way to do it after Itagaki left was to add, remove and change so many things that Ninja Gaiden Sigma 2 would be considered an independent game rather than a mere port. It worked: although the levels, combat system and enemies are pretty much the same, the playing experience is quite different.
 * For Ninja Gaiden 3 (PS3/360), there is Razor's Edge (Wii U, and then to PS3/360).
 * Ninja Gaiden Trilogy for the SNES can technically be counted as one for the NES series, though it winds up as a subversion. It uses the same 8-bit graphics, but in a couple levels in The Ancient Ship of Doom that had amazing 8-bit multiple parallax scrolling backgrounds, became single static scrolling backwards. It was actually a downgrade.
 * Up to Eleven: The first Xbox Ninja Gaiden title was already a violent game, but its sequel makes the first game look pretty tame. Fights against large groups of enemies are essentially guaranteed to turn into bloodbaths as Ryu dismembers enemies and, with the right weapons, can cut enemies in two.
 * Forget the clean cuts. Certain weapons can make body parts explode on impact. Extended use of those weapons can leave gibs on the floor as well as the walls everywhere you go.
 * The blood and body parts remain on the ground (or walls) for as long as you are playing the level with any enemy that doesn't dissolve upon being defeated. Ah, the wonders of technology.
 * The Verse: Ninja Gaiden and Dead or Alive are one in the same universe, with the modern trilogy marking the earliest events, followed by the NES trilogy, and capping off with the Dead or Alive tournaments as the lastest.
 * Visible Silence: Made famous by the NES titles.
 * "Wake-Up Call" Boss: Murai, the boss of the first level of the Xbox game, was a classic example of this.
 * Almost every subsequent boss serves as this, popping up if only to beat the living shit out of you for thinking the rest of the game would be smooth sailing.
 * Alma, easily.
 * Wall Jump
 * Wall of Weapons: In Muramasa's shop.
 * Warmup Boss: Surprisingly, most of the early bosses in the NES games were this.
 * What Measure Is a Mook?: For a series that took much joy in slicing and dicing opposing mooks, Ninja Gaiden 3 seems to be turning that into a plot point. Also, when you perform the fire-dragon Ninpo the first time, the mooks around drop their weapons and stop fighting; you have the choice to coldly finish them or let them live (it happens in Normal mode only).
 * What the...?!: In the original trilogy, this is Ryu's version of an Oh Crap moment. He tends to draw these like a moth to a flame.
 * Lampshaded by The Angry Video Game Nerd when he says, "What was he gonna say? 'What the fuck?'".
 * At the final boss battle against Clancy, Ryu instead stutters out Clancy's name upon seeing Clancy's monstrous form.
 * Wolverine Claws: The Falcon Talons.
 * World of Buxom: Only female children are exempt from it.
 * Wrestler in All of Us: Guillotine Throw and Izuna Drop. Ayane in Ninja Gaiden Sigma 2 has a scissor lock in place of the Guillotine Throw.
 * You Don't Look Like You: After years in the shadows, Irene Lew was brought back into the continuity in Dead or Alive: Dimensions, and she changed a lot. Being another character rescued from the classic NES series aside Ryu himself (who didn't change that much), Irene was updated in every single manner from Fan Service Pack and Adaptation Dye Job to Not as You Know Them; just to hit the point home, you see Sonia from the Xbox series?.
 * You Killed My Father: Ryu's motivation to fight Jaquio in the first NES game, all the more depressing because.
 * Your Princess Is in Another Castle: After releasing your father and defeating Big Bad Jaquio, you still have to deal with the demon he was trying to release. Much easier than the previous boss fight, fortunately.
 * You Shall Not Pass: Robert's battle against the demons in the second NES game.
 * Actually said by the spider-demon boss that ends the first level of the Xbox Ninja Gaiden II.

HARD TO BEAT!!