Franchise / Metroid

For True Peace In Space...

"See you next mission!"

— Samus Aran

Metroid is a series of games produced by Nintendo that began in the 1980s, and is best known for being the Trope Maker for the exploratory Metroidvania genre. They star the armored Bounty Hunter Samus Aran, with most installments revolving around her interactions with dangerous energy leeches called Metroids and her quest to annihilate the Space Pirates that plague the galaxy and killed both her human birth parents and adoptive bird-like Chozo family. Gunpei Yokoi (the mind behind Nintendo's early portable gaming hardware like the Game & Watch and Game Boy) and Yoshio Sakamoto (who would go on to produce the WarioWare and Rhythm Heaven series) are often the most credited for the franchise's creation.^note To paraphrase The Other Wiki, the core creative team that birthed the series consisted of Satoru Okada (created the basic concept of the series as being the "anti-Mario"), Yoshio Sakamoto (character designer who was "forcefully asked to participate" in the creation of the first game, only to become the overseer of the franchise going forward), Makoto Kano (scenario writer), Hiroji Kiyotake (character designer), and Gunpei Yokoi (who headed the R&D1 division and thus served as the producer).

The Metroid franchise is somewhat unusual among Nintendo's library for its substantial continuity, and holds the honor of being one of the first Platformer franchises to showcase an explicit overarching story. Case in point, the first game, released in 1986 on the NES, deals with Samus's assault on the Space Pirate base on Zebes, where she first encounters the Metroids. After defeating the Space Pirates' leader, Mother Brain, Samus is dispatched in the (Game Boy) sequel, Metroid II: Return of Samus (1991), to hunt down and exterminate the species on their home world. The end of this game segues directly into (Super Nintendo Entertainment System) Super Metroid (1994), where the final larval Metroid is stolen by Space Pirates who take it to a rebuilt base on Zebes.

The series lay dormant for years afterward, skipping the Nintendo 64 entirely (outside Samus being a fighter in Super Smash Bros.), primarily because series director Yoshio Sakamoto had no idea how to follow up Super Metroid, which decades later is still regarded as one of the best games in the genre. It didn't help that the other creative force behind the series, Gunpei Yokoi, was no longer available, having left Nintendo following the debacle that was the Virtual Boy. As the lead designer of Nintendo's most notorious flop, he took responsibility for it and left the company of his own volition.^note Though to be fair, he was planning to leave Nintendo regardless. The Virtual Boy just meant that he found himself doing so on a sour note. Tragically, he was killed in a traffic accident shortly after in 1997, robbing the game industry of one of its greatest creators.

Come the Turn of the Millennium, however, the Metroid series would not only make its return, but also find itself branching in two different directions. One path would continue to follow the franchise's side-scrolling roots and lean into its Alien inspirations, showcased with the release of Metroid Fusion (Game Boy Advance) in 2002. In it, the Metroid home world had become overrun by shape-shifting X parasites that the Metroids had actually been keeping in check before Samus drove them to extinction. After a life-threatening run-in with one of these parasites, Samus finds her life saved by a vaccine containing what remained of the infant Metroid from Super. The resulting mission to contain the x parasites on a nearby research station resulted in the most linear but dynamic game in the series up to that point.

At the same time, Nintendo had made the controversial decision to move the series to 3D on the GameCube, with American Retro Studios at the helm. Metroid Prime emerged as an unusual FPS-adventure title, set between the first and second games. While the shift to becoming an FPS was initially met with confusion and doubt from fans, and raised concerns that Nintendo was merely trying to leverage the series to compete with Microsoft's Halo: Combat Evolved (which was shaping up to be a Big Deal, even during development), the result won fans over and received much critical acclaim, including "Game Of The Year" awards from many publications. Most of the maze like tunnel game play from Super Metroid was retained, and reviewers found new content to make up for what wasn't kept in transition.

The original Metroid was remade for the Game Boy Advance a year later as Zero Mission. Zero Mission was less open ended than the original at first glance but allowed siginificant Sequence Breaking and added a new epilogue that expanded on our heroine's backstory for the first time in-game, revealing that the Space Pirate homeworld of Zebes not only used to be occupied by the Chozo, but was also where Samus spent her formative years. Meanwhile, the 3D installments would become a franchise in their own right, overseen by Kensuke Tanabe (who had previously worked on the Super Mario Bros. and The Legend of Zelda series) with varying levels of input from Sakamoto. Prime was succeeded by Metroid Prime 2: Echoes (GameCube) and Metroid Prime 3: Corruption (Wii), which continued and concluded the first game's Phazon storyline, with only a brief aside for a handheld adventure via Metroid Prime: Hunters (Nintendo DS). Or so it seemed, until another spin-off game (Metroid Prime: Federation Force for the Nintendo 3DS) released in 2016 to lay the foundation for Metroid Prime 4, which was announced the following year. Prime 4 was initially victim to a Troubled Production, and currently has no given release window. Tropes exclusive to this sub-series belong here.

After Corruption, Sakamoto would give 3D a try himself with 2010's Other M (Wii), an Interquel taking place between Super and Fusion which attempted to combine gameplay elements from both the 2D games and the Prime series, and forwent the franchise's usual use of Story Breadcrumbs in favor of a heavier focus on story and more linear progression than even Fusion. It was developed by the unusual combination of what remained of the in-house team responsible for the Metroid series^note (after the release of Zero Mission, Nintendo's R&D studios — which included the 2D Metroid team — had been restructured to serve a supervisory role over external projects rather than create their own) and Koei Tecmo's Team Ninja studio. The final product was poorly-received by fans, causing the franchise to take a brief hiatus until the release of the aforementioned Federation Force. 2017 would see the mainline series return to 2D (well, now 2½D), with Sakamoto's team now working alongside MercurySteam for Samus Returns, a remake of Metroid II for Nintendo 3DS. Samus Returns, like Zero Mission, added additional story content: this time setting up vital plot details for 2021's Metroid Dread for the Nintendo Switch, the long-awaited sequel to Fusion that had gone in and out of production for the past two decades. Concluding the storyline revolving around our heroine's relationship with the eponymous creatures, the game sees Samus investigating the far-off planet ZDR for any remnants of X parasites, only to find herself attacked by a mysterious Chozo warrior and hunted down by seemingly defective Federation robots in the process.

Across the entire franchise, a number of characteristic elements have persisted, such as the continuous string of upgrades which Samus acquires over the course of the game, most notably the "Morph Ball" (or "Maru Mari," one of several translation oddities), which allows Samus to roll into the shape of a small ball, for better maneuverability in areas where this shape is more convenient.

Being the codifier, this is one of the two best known series of the Metroidvania genre — Action-Adventure/Platform games with an emphasis on exploring a continuous non-linear world and finding powerups to advance. Technologically, the original Metroid is noteworthy as one of the first multi-direction scrolling platformers. Its North American release was also the first game to use a password system to save progress. The Japanese release of Metroid for Nintendo's disc-based system allowed the players to save their progress on the disc; the cartridge-based US system lacked this ability, so the game presented a 24-character password which encoded the state of the game, allowing the player to resume his or her progress later. This also (unintentionally) allowed players to "hack" the game, giving Samus various upgrades upon starting the game if the correct values were put into a password.

The ending of the original Metroid is a Tomato Surprise: if the player did sufficiently well, they are then treated to a stunning-for-its-time revelation: Samus Aran's armor is removed, revealing the bounty hunter to be a shapely woman (by 8-bit standards). This reveal is also in most of the other games, although no longer a surprise. Those who Read the Freaking Manual would see that Samus is openly referred to as female by Metroid II.

Though Samus herself has never appeared on television (except in commercials), Mother Brain was featured as the Big Bad of the Nintendo-themed animated series Captain N: The Game Master. (Reportedly, the production staff actually didn't know about Samus); the comic book adaptation introduced her as the Sixth Ranger/The Lancer. A live-action feature film based on the franchise was optioned after Metroid Prime was successful, with John Woo of all people rumored to direct, but appears to have lapsed. By the tail end of The New '10s, however, some in Hollywood have expressed interest in pulling the film out of Development Hell, including Ronda Rousey, Jordan Vogt-Roberts, and Brie Larson. Only time will tell if the movie ever gets made.

Games in the series

Mainline Games

• Metroid (NES, 1986): The wicked Space Pirates have stolen a Metroid from Federation researchers, and it is up to Samus Aran to track them down to Planet Zebes and foil their plans to weaponize the energy-feeding organisms.
  • Metroid: Zero Mission (Game Boy Advance, 2004; remake)
• Metroid II: Return of Samus (Game Boy, 1991): Faced with a potential disaster from the Metroids, the Federation sends Samus to their origin world of Planet SR388 on a mission to curtail any threat the Metroids may pose by completely exterminating the entire species.
  • Metroid: Samus Returns (Nintendo 3DS, 2017; remake)
• Super Metroid (Super NES, 1994): One lone Metroid larva survives from SR388, which Samus turns over to Federation scientists, only for the Space Pirates to abduct it and restart their plans to weaponize the Metroids on Zebes.
• Metroid Fusion (Game Boy Advance, 2002): Samus has a life-changing encounter with the mysterious X-Parasites, her life barely saved by a vaccine created from the DNA of their natural predators the Metroids. Now, the X-Parasites have taken over a space station, joined by a powerful parasite controlling her old suit.
• Metroid: Other M (Nintendo Wii, 2010): An interquel between Super Metroid and Fusion, this game sees Samus join forces with old friends from her days as a Federation soldier to investigate a derelict space station, the "Bottle Ship."
• Metroid Dread (Nintendo Switch, 2021): The X-Parasites, thought to be eradicated, appear to have survived on the remote planet of ZDR. Samus departs to finish off the X, while also contending with implacable killing machines known as the E.M.M.Is.

Metroid Prime sub-series

• Metroid Prime (GameCube, 2002): Taking place between the first two games, Samus investigates the remote planet of Tallon IV, where the Space Pirates have set up a base in the hopes of harnessing a new — and lethal — energy known as Phazon.
  • Metroid Prime Pinball (Nintendo DS, 2005; pinball adaptation)
  • Metroid Prime Remastered (Nintendo Switch, 2023; Updated Re-release)
• Metroid Prime 2: Echoes (GameCube, 2004): Samus travels to a distant planet named Aether in search of a platoon of missing Federation soldiers, but upon making planetfall is attacked by mysterious shadowy creatures and encounters a Phazon based copy of herself, Dark Samus.
• Metroid Prime: Hunters (DS, 2006): An interquel between the first two Prime games, Samus travels to the Alimbic Cluster to investigate a psychic message alluding to an "Ultimate Power" hidden among the planets and space stations therein. She's not alone, however, as other bounty hunters have come to claim this power for themselves.
• Metroid Prime 3: Corruption (Wii, 2007): All-out war breaks out across the galaxy as the full might of the Space Pirate military, now forcefully subverted and brainwashed by Dark Samus, attacks multiple Federation planets with powerful new Phazon weaponry in an unprecedented show of force. Now, with Federation worlds in peril, Samus sets off to cleanse the galaxy of Phazon's taint once and for all.
• Metroid Prime Trilogy (Wii, 2009; Compilation Re-release)
• Metroid Prime: Federation Force (3DS, 2016): Still reeling from the aftermath of the Phazon War, the Federation military launches Project Golem, an initiative to form mechanized battle walker squads to eliminate the Pirate threat once and for all. As the Federation Force deploys to the remote Bermuda System, what starts as a routine survey mission quickly becomes something far more dangerous.
• Metroid Prime 4 (Nintendo Switch, TBA)

Comics and Manga

All Comic and Manga adaptations can be read here.

• Super Metroid (1994): A loose American adaptation of Super Metroid released in Nintendo Power magazine; while the story itself is non-canon, some of its characters were integrated into later portrayals.
• Super Metroid (1994): A non-canon Japanese adaptation of Super Metroid done in a comedic Yonkoma format, released in Shonen Oh! Comics' Game Comics magazine.
• Metroid (2002): Samus Aran's Backstory, the latter half doubling as an adaptation of Metroid Zero Mission.
• Metroid Prime (2002): A 24-page depiction of the game's story released in Nintendo Power magazine.
• Metroid: Samus and Joey (2003-2005): A manga series that depicts Samus as a reluctant mentor to a boy named Joey, who wants to be a hero like his father. The final story arc had its title changed to Metroid EX: Samus and Joey.
  • Rebirth of Samus: A one-shot manga included in the volume one collection of Samus and Joey, depicting the beginning of Fusion.
• Metroid Prime: Episode of Aether (2005-2006): An alternate retelling of Metroid Prime 2 written by Hisashi Matsumoto, in which survivors of the doomed Galactic Federation expedition team up with Samus.

Miscellaneous

• Metroid: Zebes Shin'nyuu Shirei (1986): A Gamebook adaptation of the original Metroid.
• Blood of the Chozo (1995): An interactive online story run by Nintendo Power Source.

Other games featuring Metroid content

• Animal Crossing series
• Dead or Alive: Dimensions (Includes a Metroid-based stage location)
• Fatal Frame (Features the Zero Suit as an unlockable outfit in both Fatal Frame: Mask of the Lunar Eclipse and Fatal Frame: Maiden of Black Water)
• Galactic Pinball (Virtual Boy Pinball game wherein you could play a short Shoot 'Em Up segment using Samus's gunship if you meet the right conditions on a stage)
• Kirby's Dream Land 3 (The "Iceberg 2" mission requires you to destroy several Metroids for Samus Aran)
• Monster Hunter 4 Ultimate (Features both the Varia Suit and Zero Suit as DLC costumes)
• NES Remix series
• Nintendo Land (The Metroid Blast minigame)
• Super Mario RPG (A cameo from Samus in which she states that she is resting up to fight Mother Brain, along with a Samus doll Easter Egg in another location)
• Super Smash Bros. series (Features Samus, Zero Suit Samus, Ridley, and Dark Samus as playable characters, along with various other kinds of Metroid content in the form of stages, items, trophies, etc.)
• Various amiibo-compatible games have Metroid costumes and skins available that are unlocked by Metroid figures^note Two figures of Samus are part of the Smash Bros. line; while two other versions of Samus, a Metroid, and an E.M.M.I. are part of a Metroid line of figures.

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The Metroid series provides examples of:

#-K

• 11th-Hour Superpower: Beginning with Super, most Final Bosses have a weapon used only against them.
• Abandoned Laboratory: Common to the series, sometimes not so abandoned. Fusion and Other M take place in space stations made of these.
• Abnormal Ammo:
  • Samus has been shot at with explosive stingers, lava grenades, super cooled plasma, high density neutrinos, and contaminated water.
  • Samus herself has fired plasma, super-cooled plasma, ice, lava grenades, electromagnetic blasts, standard electrical blasts, concentrated light energy, concentrated dark energy, matter/antimatter, sonic booms, miniature black holes, and various other things out of her own beam cannon. And that doesn't account for projectile weapons - missiles, super missiles, ice missiles...
• Action Girl: One of the earliest video game examples, and easily one of the most well-known. While she wasn't even close to being the first playable female character by a long shot (a Hardcore Gaming 101 article places her as #32), what's notable about Samus is that she is the last woman standing of a wave of 1980s video game heroines who managed to survive into modern pop culture and remains quite influential as the star of her own franchise. Most of her fellow female contemporaries have been long forgotten, with the closest comparison to her probably being Athena Asamiya who debuted in Psycho Soldier (also in 1986), but later migrated to The King of Fighters and is now one of many playable fighters in that series lineup.
• Aerith and Bob:
  • Several enemies have weird names like "Desgeega" or "Holtz", or portmanteau names like "Crocomire" and "Sidehopper". A seahorse-like enemy in Norfair that spits fire at you? "Dragon".
  • Ridley, the giant Space Dragon/Pirate Commander, who's an example of this trope as he has the completely normal human name of Ridley despite being a Dragon Space Pirate Alien. What are the other aliens' names? Kraid, Phantoon...
  • Samus is the only human to appear in the series with a name that isn't immediately recognizable in modern language (it's actually Greek in origin, the name of a 3rd century Macedonian poet). Even her parents are named "Rodney" and "Virginia" in the manga.
• After Boss Recovery: Many bosses and mini bosses drop tons of health and ammo refills when you beat them. Justified in Fusion as all the bosses and enemies are made of X Parasites that Samus absorbs to recover health/ammo, so it makes sense that the bigger bosses have more potent X for her to eat.
• Air-Vent Passageway: Applies to all kinds of ducts/tunnels, with the Morph Ball. Subverted in Zero Mission, when after losing her armor, Samus must crawl through said tunnels, and she's far from the only creature who can use them.
• All There in the Manual: The games are easy to understand plotwise on their own, but there's quite a bit of canonical backstory for both Zero Mission and Fusion, as well as the entire franchise on the whole, to be found in the manuals and the two-volume manga. Most notably, the fact that the Metroids were created by the Chozo only comes up in the manual for Fusion, and wasn't shown or mentioned in-game at all until Metroid: Samus Returns.
• Always Chaotic Evil: Averted by the space pirates. Samus never encounters one that isn't evil, but she does find various logs and transmissions confirming there are in fact space pirates who have non-evil tendencies. Taking actions or even expressing opinions that reveal these tendencies quickly get them executed.
• Amazonian Beauty: Over six feet tall, clad head to toe in her Power Suit, regularly takes on death-defying missions that would turn away most others, and is known to appear in revealing outfits in the endings of the games.
• Ambidextrous Sprite: Averted in all 2-D games after the first; Samus has different sprites for all directions. Interestingly, some differentiated left/right sprites are in the ROM of the original game, but are unused.
• Anachronic Order: The first four games were in order, but starting with Metroid Prime they started releasing interquels and remakes. It would take 19 years for Dread to finally pick up where Fusion left off.
• Antagonist Title: Played with; Metroids are commonly weaponized by the Space Pirates, but they're only the main antagonist in Metroid II / Samus Returns, where the mission is specifically to eradicate the species.
• Archaeological Arms Race: Both the Space Pirates and the Galactic Federation reverse-engineer ancient Chozo technology with varying degrees of success.
• Arm Cannon: Samus is a type 1, though her arm is not replaced by a cannon, just inside of it instead of holding it. The cannon can open up like a maw to grab things in Prime 3 (it had opened up prior to shoot missiles, that was the first time she used the feature so mundanely). The Space Pirates and Ghor have been seen with type 2, attached to the wrist.
• Apocalyptic Log:
  • The Prime games have the Chozo, Luminoth and Bryyonian lore entries detail the fall of their respective races to Phazon corruption, the Ing and a Magic Versus Science civil war, respectively.
  • Also from the Prime games, the Space Pirates usually have some logs describing how "the Hunter" (their name for Samus) is rampaging through their installations.
• Art Evolution: Samus' famous power suit, which grew its distinctive Shoulders of Doom in Metroid II when the Game Boy's technical limitations prevented implementing the Power Up Full Color Change from the original Metroid. For years, this change was treated as a Retcon, showing the shoulders in flashbacks and the like whenever covering the events of the original game, but Zero Mission and supplementary issue finally resolved the issue — Samus lost the original Power Suit (original design) after the events of the main game, and gained the "Legendary Power Suit" (New Shoulders Included) during her exploration of Chozodia.
• Artificial Brilliance: In Fusion, once you get the Varia Suit, absorbing cold X will heal you rather than hurting you. After you absorb a few, they'll realize what's happening and start to avoid you.
• Artistic License – Military: The major military force in the series setting is the Galactic Federation Army, with the English versions of the Prime games adding a Marine Corps. In Metroid Prime 2, the ranks of the deceased Federation Troopers on Aether show the Marine Corps uses a mix of army, marine, and naval ranks. Specialist is an army-exclusive enlisted rank^note As of the time the game released. As of 2021, the Specialist rank came into use with the U.S. Space Force for its first four enlisted ranks, Lance Corporal and Gunnery Sergeant are Marine-exclusive ranks, and the officer ranks are all naval based with Lieutenant Commander, Commander, and Captain (as in, a senior officer one rank below flag officer level; the Captain rank in a non-naval branch would be a junior officer). This confusion doesn't exist in the Japanese versions of the Prime games as the "Marine Corps" doesn't exist in them: all of the Federation's military falls under the Army.
• Artistic License – Physics: Rarely shows up in detail since most of the science fiction aspect is reasonably well-thought-out, but becomes glaringly obvious when it comes to the various destroyed planets. Two of them—SR388 and ZDR—are destroyed, in both cases exploding, once a space station crashes into them. In reality, a space station that was capable of destroying a planet on impact would be too big to orbit said planet in the first place. As for the detonation sequence that destroys Zebes, nothing is ever made of how this was arranged or the resources necessary to do so.
• Asteroid Thicket: Used in Super and Fusion, where something crashes into an asteroid in each. The asteroids look like they're only a few hundred feet across, and tightly packed.
• Attack Its Weak Point: An ever-increasing number of bosses throughout the series have this. Starting with Mother Brain in the original Metroid (though you have to make the weakpoint yourself by blasting a hole in her glass case), then continuing with all the "mutated" Metroids in Metroid 2. In Super Metroid, Kraid and Crocomire are only vulnerable to shots to the mouth, Phantoon must be shot in the eye, and Draygon must be shot in the belly (or electrocuted with the Grapple Beam).
• Attack of the 50-Foot Whatever
  • Kraid in Super Metroid and Zero Mission is twice the size of the screen. The Final Boss of Super isn't quite as big, but still counts, being about as tall as the screen is.
  • Quadraxis of Metroid Prime 2 is titanic. In fact, it's so large that rather than keeping your distance and shooting it, you have to climb on it with the Spider Ball to even reach its weak points.
• Backtracking: Obtain previously inaccessible power-ups, curb-stomp previously lethal opponents with your new upgrades, and discover brand new shortcuts and secrets — all by the magic of backtracking through every area of the game at least twice. It is so integral to this series that fans will frequently complain if the developers remove the ability to backtrack, such as in Fusion and Other M. Even those at least give full access to the game world once Samus is fully upgraded.
• Bag of Spilling
  • Samus never manages to keep her fully powered-up suit between games, though more later entries at least let her hang onto the Varia upgrade. Usually. In games where she keeps the Varia (Excluding the first Prime, see below) it does nothing.
  • The Long Beam has only been an actual powerup in the original game and its remake; every other game gives Samus its effects even if she visibly loses all her other powerups. Metroid II also starts her off with about 30 missiles, since they're needed to even damage the Metroids she's hunting.
  • Played with in Metroid Fusion. Samus kept all of the weapon upgrades to her power armor. Unfortunately, her power armor was infected with a parasite which is now using all of those weapon upgrades to try to kill her.
  • And in Prime. While trying to escape the ship at the beginning of the game before self destruction, the ship violently rocks to the side, and a small explosion hits her from behind, causing her to slam against the wall, which causes malfunctions with most of her equipment.
    • Prime 2 begins with a fairly well equipped Samus, but is pretty shortly mugged by aliens and has her upgrades stolen from her. The sudden feeling of impotence is felt by both Samus and the player. To recover many of her upgrades she must find her attackers and fight them, one at a time, while they use her own upgrades against her.
    • Prime 3 has Samus simply start off without any of her items from the previous adventure, but she does retain a few of her power ups such as the Space Jump Boots, Morph Ball with its bombs, and her Charge Beam. Word of God states that they scrapped the idea of Samus having her powers in the start and then losing them right after since it was getting too predictable and boring. invoked
  • And again in Other M. Samus has her full arsenal, but is working with the military in this one and needs authorization to use parts of it. Unfortunately this leads into a Voodoo Shark situation when the restrictions on her weapons shouldn't cover her nonoffensive equipment, and she won't activate gear she has even in life-or-death situations. Thankfully, in one case, the damage she would take as a result of this is mercifully nerfed.
• Ball of Light Transformation: In the 3D games, Samus takes this form inside the Morph Ball, a process that the Space Pirates were unable to replicate.
• Be the Ball: One major aspect of Samus' suit is the ability to roll up into the ultra-compact Morph Ball. Naturally, she's used as the ball for Metroid Prime Pinball. The Samus and Joey manga shows that Samus actually curls up into a Morph Ball every once in a while and that she loves the feeling of being a ball, to the point she actually might just prefer it more than being human.
• Beauty Is Never Tarnished: In Fusion Samus has to have parts of her suit surgically removed and there is absolutely no scarring. There also appears to be no visible changes caused by the infusion of Metroid DNA (or Chozo DNA for that matter). Not so in Corruption, Samus's phazon corruption causes visible breakdowns on her face and she vomits at one point.
• Bee People:
  • The Zebesian Space Pirates in the manga comics will follow anyone with enough strength or charisma. In a bit of a subversion, their species can't produce "queens", so they look to other species to lead them. On their own, they're Too Dumb to Live. A fan theory even says that the Zebesians are Super soldiers bred by the smarter Space Pirates in Prime, and are MADE to be stupid and not question anything.
  • Almost literal with Kihunters. They're physically bee-like in addition to living in hives and having a "king" that commands the rest.
• Berserk Button: If Samus is pointing her arm cannon at you and you just happen to be a member of a race of intergalactic bloodthirsty aliens, don't beg for mercy. A space pirate tries this in the manga, and an already enraged Samus goes ballistic, reminding him that he was about to ignore the pleas of a little girl they marked for execution.
• Big Bad:
  • Mother Brain in Metroid / Zero Mission and Super Metroid and also Other M via a clone.
  • Metroid Prime/Dark Samus for the Prime trilogy.
  • Gorea in Metroid Prime Hunters.
  • Raven Beak for Dread.
• Big Boo's Haunt: The Chozo Ruins (Prime) and the Wrecked Ship (Super).
• Big Creepy-Crawlies: Many games have giant buglike bosses, but Zero Mission has the most.
• Big Damn Heroes: The eponymous Super Metroid in Super Metroid just before the Big Bad lands the killing blow on Samus. It is the grown up baby Metroid Samus spared, after all.
• Bio-Armor: Samus' power suit appears metal at first glance, but it may actually be organic. In Metroid Fusion, the X-Parasites, a species that infects and mimics other organisms, is able to infest and then copy Samus' armor. Metroid Dread ends with Samus becoming mostly Metroid, and her suit becomes noticeably more organic in appearance.
• Biological Weapons Solve Everything: Subverted. The Chozo created the eponymous Metroids as a biological weapon to control the rampant X Parasites on planet SR-388, which could have threatened the entire galaxy if left unchecked. Later, other races discovered the Metroids and the creatures began to spread across the galaxy, proving to be an even worse threat than the X Parasites. Then, when Samus eradicated the Metroids, the X Parasites came back stronger than ever. Further subverted in Samus Returns, as while the Chozo created the Metroids to curb the X Parasite population, they also seemingly did not intend for them to grow beyond their signature larval stage and could no longer control them. This is what led to them being locked away in a bunch of acid.
• Bittersweet Ending: Super Metroid, Other M, and Fusion.
• Body Horror:
  • The X Parasites in Fusion; Phazon in Prime. Metroids themselves count, given their habit of turning their victims into desiccated gray husks that turn to powder when touched. In Prime as well, a vague reference to Space Pirate attempts to replicate the Morph Ball that went horribly, horribly wrong. Special mention goes to Prime 3, where you can actually see the gradual effects of Phazon corruption on Samus with each Leviathan destroyed. Those eyes could curdle milk.
  • Prime 2 has the Ing, a transdimensional species of dark-matter aliens that can possess and mutate other beings/machines.
• Book Ends:
  • Super Metroid opens and closes with escapes from structures that are about to blow up.
  • Metroid and Super Metroid both take place on Planet Zebes. Samus ventures into the planet, defeats Ridley, Kraid, and Mother Brain, and escapes before the planet blows up. In Super Metroid, the end to the original trilogy, Samus ventures into the planet again, kills Ridley, Kraid, Phantoon (not), Draygon, and Mother Brain, and escapes before the planet (the escape shaft from the original game is part of the route) blows up. Fusion provides two. The end to the original trilogy had the super metroid heals and gives you a weapon to defeat the final boss, saving your life. In Fusion, the Metroid's DNA cures Samus of the X-Parasite infection (saving her life), and makes her able to absorb the X to heal her and replenish her supplies (giving her the weapon to eradicate the X). Also the ending, in which the SA-X saves your life, heals you, and gives you the weapon to eradicate the Omega Metroid.
  • Also in Fusion, both the very first boss (Arachnus) and very last boss (Omega Metroid) are from Metroid 2. Those two bosses also have the same basic design. Sharp teeth, huge claws, only susceptible to attacks on its belly. The only real exception is that Arachnus can turn into a spiky ball or shoot fireballs, while Omega Metroid is just big enough to stomp you flat.
• Boss Arena Recovery: Avoided in the first game, but Zero Mission has the rinkas around Mother Brain occasionally drop health. Notoriously, the boost guardian can destroy all the health dropping pillars in one shot, denying you any recovery in a boss arena that drains your health.
• Brain Monster:
  • In Metroid, the final boss, Mother Brain, is a massive brain in a tank, with a laser shooting eye. It's stated that it started off as an organic computer built by the Chozo, which took command of the Space Pirates.
  • In Super Metroid, Mother Brain reappears as the final boss, this time as an "acranial" example, having gained a massive mechanised body.
  • The Federation created Aurora Units, introduced in Metroid Prime Three Corruption, although the brain part is not as noticeable, as they are much more mechanical than Mother Brain, as is the monster part, since they are all affable allies of Samus.
  • Master Brain was created by science team operatives in the Bermuda system with then new alien technology they discovered so it could lead the space pirates there while they got back to scientific research. It serves as the main antagonist of Metroid Prime: Federation Force.
  • The Central Units from Dread are visibly based on Mother Brain, especially after their armored shells are destroyed and the brain portions become visible. Given that they are affiliated with the Mawkin Chozo, it's very likely they are the same model of AI that Mother Brain herself was.
• Breath Weapon: Ridley, as he's a Space Dragon. Also Kraid and One-Winged Angel Mother Brain in Super Metroid. In the Prime series, Sheegoths, the Parasite Queen, and the titular Metroid Prime.
• Broken Bridge:
  • Sometimes intentional to, at least try to, prevent Sequence Breaking.
  • Even after seventeen years, people are still discovering new tricks like this.
• The Cavalry:
  • Two times, one in Super Metroid and another in Fusion. In Super Metroid, Samus was losing in a Curb-Stomp Battle with a One-Winged Angel Mother Brain, after taking a blow from her ultimate attack. Before the job can be finished, the huge Super Metroid that had earlier attacked Samus but decided to spare her on account of it formerly being the baby metroid Samus had spared, zooms in, drains Mother Brain's energy, and then gives it to Samus, restoring her to full health and granting her the Hyper Beam. Then, it dies while shielding Samus from Mother Brain's attacks. Cue Samus curbstomping Mother Brain.
  • And then in Fusion, Samus had beaten SA-X, plotted the B.S.L. Station on a collision course with SR-388, and was on her way to her ship to escape. But when she gets to the docking bays, the place is a mess, her ship is missing, and there is a huge shedded skin on the floor. Suddenly, an Omega Metroid comes in and screeches at Samus. With one claw swipe, Samus is knocked down to one HP and immobilized. Before the Metroid could kill her, the SA-X appears and blasts its chest with the Ice Beam, but it is defeated by it. However, Samus absorbs its Core-X, which restored her Ice Beam ability, and proceeded to blast the Metroid to dust.
• Canon Foreigner: Captain Nemo in the old Metroid Manga/Strategy Guide, and moveset wise, the Zero Laser from Super Smash Bros. Brawl and the "Chozo Blood Rights" ability from Marvel Ultimate Alliance (she was Dummied Out from the latter game, however).
• Canon Immigrant:
  • Several characters from Benjamin Itoh's Super Metroid comic (published in Nintendo Power) appear in Nintendo's canon manga. Also as in the old comic, Ridley appears to speak English, though this isn't reflected in-game.
  • In the instruction manual for the original Metroid, there is a picture of a Federation council meeting, with what appears to be a Chozo in attendance. As of the 2004 Manga, this has been made canon as well.
• Cap Raiser: Tanks, Energy Tanks, Missile Tanks, Power Bomb Tanks, if it make limit number go up, it's a tank.
• Catastrophic Countdown
  • Super Metroid plays it straight, twice. When Ridley escapes the space colony in the beginning, an announcement claims that the colony's self-destruct has been activated, urging immediate evacuation. Naturally, the whole place starts shaking, steaming, blowing up, and even rocking back and forth quite impressively. Later at the end of the game, the entire planet starts exploding and flooding with acid, because a "Time Bomb" has been activated. This part even reads, "Time Bomb set!" as a nod to the first game
  • Other M. An AI voice announces over an intercom that a self-destruct sequence will detonate in about five or so minutes. For some reason, your escape becomes riddled with burning debris and wreckage.
  • The first game is a bit of an interesting case. While the NES original averts it entirely ("TIME BOMB SET | GET OUT FAST!", plus a countdown, that's it), Zero Mission retcons in a straight example (the "time bomb" causes explosions and flames well before going off) and an aversion (the Pirate Mothership).
• Charged Attack: Charge Beam, the beam combos, the Shinespark.
• Charge Meter: In the Prime games, discounting Hunters, the arm cannon has a meter to build up when holding down fire. It even has practical purpose when using seeker missiles.
• Chekhov's Gunman: The Etecoons and Dachoras in Super later save your butt in Fusion, since Samus saved theirs during Super's final countdown.
• Chekhov's Skill: Every power-up becomes useful to go to unreachable areas/items.
• Chest Monster: Torizo in Super Metroid mimics a Chozo Statue early on, and reappears late in the game. One of the X-Cores in Metroid Fusion also impersonates a Chozo Statue (most likely a Torizo, considering hosts need to be organic), and another Core X impersonates one named Nettori while giving it power over vegetation and the Plasma Beam.
• Cliffhanger Wall: Fusion spent 19 years as the final game in the series' timeline, ending with Samus causing the destruction of the B.S.L. station and the planet SR-388 in order to stop both the Federation's secret cloning research on Metroids, and the spread of the deadly X Parasites, leaving her future relationship with the Federation unknown beyond an in-universe acknowledgement that she will most likely have to face trial for her actions. During the intervening years between it and the release of Dread, the franchise saw six interquels by way of the Metroid Prime sub-series (seven, if you count Prime 1's pinball adaptation) plus Other M, and two remakes.
• Climax Boss: Nightmare in Fusion. Especially after playing Other M.
• Collector of Forms: The X Parasites are shapeshifters that can mimic any lifeform... but they must first absorb DNA from that lifeform. This typically involves infecting a living host, or absorbing the DNA from biomatter (as seen with the Core-X that absorbed Ridley's DNA from his preserved corpse). X Parasites that possess DNA of multiple lifeforms can change between their forms or even combine them into hybrid forms.
• Color-Coded for Your Convenience:
  • Doors are colored depending on what weapon the player needs to shoot them with to open. Return of Samus and Fusion are the exceptions. (Return of Samus only has Missile Doors, which would be red if the game had color.)
  • In Fusion the doors are color-coded, but by security-clearance. Samus needs to find the override controls for each security level to unlock them, after which any beam will do the trick. This becomes a plot point, as unlocking the controls also allows the X-parasites to spread further through the station.
• Comic-Book Adaptation: There are tons of them. Two of which are tongue-in-cheek semi-guide books, one is a Nintendo Power comic, one is loosely based upon the first Metroid Prime, a prequel manga and a manga based on pre-Prime 2. Let's not even get started with Samus and Joey series...
• Completion Meter: Later games have a percent counter that rises as you collect items.
• Conlang: The Chozo have their own fictional language, which was first seen inscribed on the sides of Samus' Gunship in mysterious characters that translated directly to English. The language is finally spoken with its own vocabulary in Dread by the game's Chozo characters and Samus herself.
• Continuity Nod:
  • The remixed music in the latest installments, plus pieces of the original Brinstar and Tourian in Super Metroid. Possibly also parts of Kraid and Ridley's lairs, although Kraid's "Lair" (especially the piece in question) is very far from where it ought to be. Super Metroid's "Item Room Ambience" is a (particularly odd/creepy) remake of the original Metroid item room theme.
  • The lower Yellow Door connecting Crateria and Chozodia? Turns out it's part of the Wrecked Ship From Super.
• Convection, Schmonvection: Averted, in a rare video game example.
  • Without her Varia Suit, Samus can't even get near lava without being burned, and walking into superheated rooms will cause her to take continuous, non-trivial damage. Most Metroid games make the lava dangerous to touch even when the Varia Suit provides resistance to convection; only more powerful armors like the Gravity Suit (in the 2D games) allow her to walk in lava without getting hurt. In Fusion, she gains a vulnerability to extreme cold as well, as a side-effect of the Metroids DNA she was injected with, which can be overcome with the Varia.
  • Only two games play Convection, Schmonvection straight: The original Metroid and Metroid II: Return of Samus, in which most players can't tell it is lava until they explore a section of Metroid Fusion built to simulate the game.
  • Super Metroid plays this straight in Tourian, the final area of the game, probably because they weren't expecting anyone to get that region without collecting any of the suits. It's also worth noting that not all areas of Norfair (even Lower Norfair) cause damage to the player, but it mostly seems to be dependent on whether there's lava in the region. Naturally, the reverse boss order speedrun (which contains some truly magnificent platforming) takes full advantage of this.
• Cool Starship: Samus' gunship, all Three of them. The loaner ship she gets from the Federation after totaling her own in Fusion's opening may count as well.
• Cowboy Cop: In the manga, Samus herself, as well as her partners Mauk and Kreatz.
• Critical Annoyance: Dua-dua-dua-dua-dua-dua — few things are better motivation to search for energy.
• Critical Existence Failure: As long as that suit has just one point of energy, she'll be okay.
• Cute Bruiser: Samus' pet, Pyonchi, is a rabbit-squirrel from her home planet, who has been known to beat the crap out of schoolyard bullies, complete with a sign saying "Play nice."
• Cuteness Proximity: Samus had this, or more accurately "roundness proximity", often in the gag manga strategy guide for the first game.
• Cybernetics Eat Your Soul:
  • For the most part averted, as most characters get along just fine with their cybernetically-enhanced Powered Armor.
  • Ghor is a special case. Though he's only 6% organic, he's a very nice guy. When he interfaces with computers or his battle armor, though, he becomes aggressive and bloodthirsty.
• Damn You, Muscle Memory!: Most gamers familiar with platformers go from left to right out of habit, but the original Metroid forces you to go left in the first area to get the Morph Ball and continue... which is Fridge Brilliance, as Metroid was one of the first games featuring a sprawling open ended world. Making players go left was a way to make players realize that this wasn't just some sort of sci-fi Mario/Pitfall/Whatever game. Perhaps in homage to this, the path to the right is blocked off entirely at the start of Super Metroid (until you get the speed booster and/or power bombs) and for the entirety of Fusion, as the only path out of the docking bay is to the left.
• Darker and Edgier: While Metroid itself is already the foremost Darker and Edgier alternative to the other Nintendo series, the earliest version of Metroid Fusion (then just called "Metroid IV") was... very unusual. It sported a "bladed" logo, a number that looked like it was torn from a claw, a darker color scheme, and a new suit that made Samus look hyper-muscled. The final version is lighthearted in comparison, but it still retains many elements of survival horror due to the ongoing threat of SA-X.
• Death Is Cheap: Ridley has evaded death every time Samus encounters him, from Never Foundthe Body, to sneakily flying away while the camera isn't looking (we saw your shadow sneaky), to getting a robo upgrade. He never actually dies until Super, but when he does, some Too Dumb to Live researchers in Other M unwittingly CLONE the bastard. He even appears as a boss in Super Smash Bros. Brawl FOUR TIMES. As Ridley, as Meta Ridley, and then again for each form in the Great Maze.
• Defeat Equals Explosion: Most bosses in the series will explode. Ridley, on the other hand, only gets this treatment once, in Zero Mission. Metroid Prime 3 subverts this with Ridley; fans noticed Omega Ridley's shadow flying away during his "death" cutscene after a mere FIVE YEARS.
• Depth Perplexion: Justified. Samus can shoot through walls, but only if she has the Wave Beam, which explicitly has the ability to penetrate solid matter. All the special beams barring ice could shoot through walls in Return Of Samus, but everything excepting the wave beam lost this property after that.
• Determinator:
  • Nothing will stop Samus Aran. And nothing will stop Ridley from trying to take her down. Well, except for his remains being on an exploding planet. Even when he's cloned, he gets to go after Samus twice before the clone dies.
  • Same with Crocomire, who comes after Samus even after ALL HIS SKIN HAS BURNED OFF. That's right. He tries to attack you as a SKELETON. And fails miserably.
  • Chronologically, Phantoon goes after Samus two games in a row.
  • The Space Pirates, although they get their space-faring asses handed to them all too often, never give up their goal of galactic domination. Their penchant for finding Phlebotinum and Sealed Evil in a Can lying around might support this.
• Destructible Projectiles: In various games of the series (Super Metroid in particular), certain projectiles can be destroyed for health or Missile refills during boss battles.
• Destructive Savior: It seems Samus cannot escape the cold hand of destruction, whether it be a large base or the entire planet. So far, her "kill count" includes Dark Aether, Phaaze, Zebes, SR388 and ZDR/Tarin, the third of which wasn't even her fault. Granted, the others were of her own doing, Phaaze because it kept popping out Phazon Leviathans to infect other planets, Dark Aether because it was just pure evil incarnate, and SR388 and ZDR so she could wipe out the X Parasites, but still. Not even space stations are safe, since the Biologic Space Labs orbital station dies with SR388. And Samus' first order of business on Tallon IV? Blow up the Space Pirate Frigate Orpheon. Doesn't count the five Space Ships/Colonies that blew up with her on board, (although most of those weren't her fault), and her own ship in Fusion's opening.
• Directionally Solid Platforms: Inverted with pitfall blocks that allow going down but not up.
• Doom Magnet: In addition, very few characters with personal connections to Samus ever survive.
  • Guess what happens to the Bottle Ship at the end of the Playable Epilogue of Other M? The music is even the same as during the escape sequence in Super Metroid.
  • Also, Ceres Space Colony. It wasn't her fault, but it still self-destructed right after she left. And then there's Samus' own ship in the Fusion prologue, but again, not her fault. She fell into a coma and the ship also collided with an asteroid. This one would've been the end for her had her ship not had an automated emergency system to eject her escape pod.
• "Die Hard" on an X: Except when it is on a space station, complete with air vent escapes and everything!
• Disney Death:
  • Ridley in Prime gets blasted by the Chozo statues into the crater. Obviously he shows up at least 3 more times, though one was due to being cloned.
  • Anthony Higgs acomplished this in Other M with some clever enemy manipulation.
• Doomed by Canon: See Foregone Conclusion.
• Doomed Hometown: Samus lives through two of these, first on K-2L and then on Zebes.
• Down the Drain: Maridia, the crashed frigate, Torvus, Sector 4 (AQA). The latter only because the environment is artificial.
• The Dragon: Ridley is a high-ranking member of the Space Pirates under Mother Brain, and is typically the second-to-last boss fought in every game. He also takes the trope to its literal extreme, being a space dragon.
• Dumb Muscle: The original Japanese strategy guide was also a manga; Samus was depicted as a trigger-happy ditz with far more strength than smarts. Although the humor here is that the reader never knows she is a female at this point, and the strategy guide never reveals it either, just basically saying at the end that you can "meet the true Samus if you beat the game quick enough." In hindsight, it's hilarious.
• Dummied Out:
  • Two very interesting things were removed at some point from Zero Mission. One was the ability to turn suit upgrades on and off from the pause menu, as in Super Metroid; fans are still wondering why this much-missed feature was taken out. (Cheat codes can turn it back on.) The second was... Crocomire! This Super Metroid boss was found in the ROM, with a full set of sprites and some movement code, but nothing else. It's possible to hack him into various rooms.
  • In turn, Super Metroid's ROM includes some interesting objects that were never used, most notably a "reflector" which would bounce any beam or missile off at a 90-degree angle. A form of this was used by two pirates in Ridley's Lair who act as a miniboss.
  • The first Metroid game on the NES had unique sprites for Samus that would have avoided the Ambidextrous Sprite trope, but those got replaced with the current sprite the game uses currently.
• Dungeon Bypass: The Shinespark allows flying across whole rooms, even through certain walls.
• Early-Installment Weirdness:
  • The 1986 design for Samus Aran gave "his" suit a large red barrel chest, tubes under both arms, a more "ray gun" barrel on the cannon, a red glove, and red boots. In addition, the artwork for enemies in the NES version of the game differed considerably from the Famicom version. In both, Kraid was a stout, yellow lizard with long green hair. Ridley, however, resembled a cute baby dragon in the Famicom art, and a bizarre horse-mouthed creature with five eyes (three down the forehead) in the NES art. Metroids had a mass of tentacles instead of fangs, making them look more like jellyfish.
  • Metroid (outside of an obscure arcade machine version) and Return of Samus have no map system whatsoever. Super was the first to introduce a map, but it only shows the rooms without highlighting any of the doors and paths that connect between them, and also highlights all entered rooms as pink — connections and alternate colors for unique rooms (mainly secret ones) wouldn't come until Fusion.
  • In the first game, Samus can only shoot in three directions — left, right, and up — and can't crouch, leaving Bombs as the only way to defeat short enemies. Return of Samus would introduce crouching to shoot low and aiming downward when in the air, Super added the ability to aim in the four main diagonal directions, Samus Returns upgraded the diagonal aim button into one that locks Samus in place and allows for full 360° aiming, and Dread allows for that same spread of directions while moving.
  • In Metroid, Return of Samus, and Super, Bombs bounce Samus upwards even when she's not in Morph Ball form, and in Super, Power Bombs bounce Samus like normal Bombs. These were both gone starting with Fusion, though Samus Returns would briefly see the latter return in a new form as the Spiderspark.
  • The first two games had beam weapons as mutually exclusive items. Picking one up would replace the other and required significant backtracking to get the other in the original game. The second made it slightly better by having multiple locations for each weapon, as well as rooms that had multiple weapons to choose from.
  • Super Metroid had an item switch function, allowing the player to turn on and off whichever upgrades they wanted. While Wave and Ice could be stacked, the Spazer and Plasma Beams were mutually exclusive. Tricking the game into turning on both led to a number of glitch beams. Furthermore, prior to the 2002 games cementing their names, the Morph Ball and Grapple Beam were respectively referred to as the Morphing Ball and Grappling Beam.
  • As for Samus' trademark Varia Suit upgrade, in the original Metroid it's simply a color swap of her original suit. The Varia Suit didn't gain its trademark shoulder pads until Metroid II, where the change in costume had to be conveyed with a proper sprite change because of the Game Boy's graphical limitations. This was both Retconned in Zero Mission to be due to Samus acquiring a more advanced Power Suit near the end of the game, which does indeed sport the shoulder pads unlike the suit from the rest of the game.
  • Missile doors used to take 5 missiles to break the lock. It wasn't until Prime that this was dropped.
  • Shinesparking in Super costs health to do, and has a unique attack after impacting a surface where Samus emits two Speed Echoes off of herself, damaging any enemies they come into contact with. Later games removed the health penalty and the echo projectiles.
  • Samus in the 2D games always has two kinds of jumps - the straight vertical jump, and the somersault she does when moving - but prior to Fusion, these two jumps were entirely separate. Fusion introduced the ability to turn a vertical jump into a downward somersault by pressing the jump button again while in midair.
  • In the first game and Return of Samus, Samus takes a bit of damage if she's in the location of a breakable block when it reforms. Super would make it so that the block simply fails to regenerate, while Fusion and Zero Mission would add an animation of the block attempting and failing to reform if she's in its spot.
  • The first two games had more Energy Tanks hidden in them than Samus was capable of holding, effectively making any spares a one-time health refill. Super is the first game where Samus can hold every Energy Tank she comes across.
• Earth-Shattering Kaboom: If Samus is on a planet, its days are numbered. See also: Dark Aether at the end of Echoes, Phaaze at the end of Corruption, Zebes at the end of Super, SR388 at the end of Fusion, and ZDR at the end of Dread.
• Easter Egg: In Super Metroid, if you return to the Surface of Zebes after obtaining the Super Missiles but before descending into lower Brinstar (when it's still raining) and use the bombs and super missiles to go into the cave on the right, you can listen to the "arrival on Zebes" music again.
• Elaborate Underground Base: Many games feature at least one (or ARE one): Tourian (both versions) in Zebes, Phazon Mines in Tallon IV, the flooded chambers of Torvus Bog in Aether, the Pirate Mines in Pirate Homeworld, and the Omega Metroids' territory in SR388.
• Eldritch Abomination: Phaaze is a living, sentient planet intent on infecting as much of the galaxy as possible with Phazon, Gorea is a starborn monster capable of assimilating anything and everything thrown at it, and Phantoon is a bizarre alien parasite ghost that can fuck with local space-time and looks a fair bit like something out of the Lovecraft playbook.
• Emergency Weapon: The stun pistol in Zero Mission.
• Emergent Gameplay: The open-ended nature of the games, especially the earlier ones, lent themselves very effectively to Sequence Breaking, Speed Running, low percent completions, and more.
• Equipment-Based Progression: The first thing you have to do in the first game is get the Morph Ball so you can roll under a ledge to the right. All Metroid games make use of this trope. Ironically, the first game's remake, Zero Mission, was the first to have several progression elements not based around new equipment.
• Eternal Engine: Tourian, and most of Fusion.
• Evil Is Visceral: Mother Brain and the Aurora Units are big brains in jars that do not look very pretty. The latter aren't evil on their own though. Starting from the first game, the Metroids themselves have visible blood vessels of some sort. In the second game, they were given an insectoid life cycle. In the third game, one of them grows really big, letting you see even more organic bits inside of the body. Same goes for Dark Samus in the Prime series: the more beat-up she gets, the more glowy Phazon innards start showing. And then the same thing starts happening to Samus herself in Corruption. The Leviathan insides are visceral too.
• Evil Doppelgänger: A common theme. SA-X in Fusion and Dark Samus in Prime 2 and Prime 3 are quite literal doppelgangers, while Raven Beak is more of an Evil Counterpart.
• Evolutionary Retcon:
  • In the first Metroid, due to graphical limitations, Kraid and Ridley are both the same size as Samus. By the time Super Metroid came around, Kraid was two rooms high, and Ridley was at least three times the size of Samus. Zero Mission retcons the Super design into canon.
  • Super Metroid also adds a "fake Kraid" that's slightly taller than Samus and much easier to kill outside of the real Kraid's room: this is both a reference to the size difference in the earlier games as well as the fact that the NES game had a fake Kraid somewhere in the area.^note It can be forgiven that many players didn't know about the fake Kraid in the original game, as Zero Mission removes it entirely, and the fake is not on the much easier route to the real one.
  • Throughout the Metroid Prime series, the Space Pirate models vary greatly, gaining a separating lower jaw and going from two to four eyes. Partially justified due to the fact the Pirates are genetically altering their troops (with varying levels of success) to enable them to conquer the galaxy.
  • It Metroid Prime 2: Echoes the Metroids of the Prime series are explained as being "Tallon Metroids"; a different breed than the SR388 Metroids encountered in the other games. This explains why the Metroids in the Prime Trilogy can be defeated without freezing them.
• Exactly What It Says on the Tin: "Choujin-zoku" roughly translates to "bird race". The Chozo are, y'know...
  • There's actually more. "Choujin" is "bird people," which is roughly what the Chozo are. However, "choujin" for "bird people" is phonetically the same as "choujin" for "superhuman."
  • The Metroids as well. "Metroid" is revealed to be Chozodian for "ultimate warrior". In the early games, Metroids were near-invincible, and by far the most dangerous non-boss enemies around.
  • And the Space Pirates are... Well, pirates. In space.
  • Samus' powers aren't safe from this either. The Speed Booster boosts your speed. The Missile Launcher launches Missiles. The Scan Visor scans things, the Thermal Visor sees heat, the X-Ray Visor sees X-Rays. The Command Visor sends commands.
• Eye on a Stalk: The Zeela, a creature that appears in Kraid's Hideout in the original Metroid and Metroid: Zero Mission and the jungle area of Brinstar in Super Metroid, has two eyes on the end of long stalks.
• Expanded Universe: Many characters and stories such as Chairman Keaton, Chief Hardy, Old Bird, and Adam Malkovich either made their first appearances, or were first fleshed out, in the Japanese manga and the Nintendo Power Super Metroid comic.

• Faceship: Samus Aran's Gunship has the design of her helmet built on it.
• Fanservice: Your reward for finishing the game with 100% completion in most games.
  • Becomes Fan Disservice in Super Metroid and Fusion when her armor blows off, leaving her in a skimpy outfit, as it is her death animation.
• The Federation: The Galactic Federation.
• Fly-at-the-Camera Ending: In Super Metroid and Zero Mission.
• Force-Field Door: A staple of the games. Doors that open simply by being shot are handwaved as being set up to keep out unwanted wildlife. Certain fluff scans suggest they don't always succeed.
• Foreboding Architecture: From the very first game we have "air tubes" which spawn a variety of increasing dangerous flying nuisances. Sometimes the enemies would not spawn, or would spawn later than normal to give you a false sense of security. Each entry in the Prime trilogy has Metroid storage tanks which inevitably are broken out of except for a rare few in Prime 1 that stay put unless you break them out yourself.
• Foregone Conclusion: Adam Malkovich sacrificed himself in Other M. Also, Ridley reappeared in that game and died. This was known as far back as Fusion. Other M also explains why Ridley fell apart so easily when you encounter the body in the freezer in Fusion and the X Parasite escapes his body. The last we of see Ridley in Other M, is a dried, gray husk after having his life sucked out of him by the Queen Metroid. And the reason the body is never seen breaking down? It's so the above scene in Fusion can play out. That was never the real Ridley. It was a clone all along.
• Freeze Ray: A vital tool of the series, both for its creative uses, and for stopping the titular threat. Subverted with Prime 3 and Fusion, which use Ice MISSILES rather than a beam, but otherwise has the same effect.
• Frigid Water Is Harmless: Played straight for the most part throughout the series, where Samus suffers no ill effects from walking in water in icy locations (minus the gravitational effects) even with the most basic power suit on. Averted somewhat with the Fusion Suit, as Samus will take damage from merely being in cold areas until she acquires the Varia Suit.
• Frozen Foe Platform:
  • The Ice Beam is the Trope Maker, appearing in the first game, Metroid. Many areas can only be accessed by freezing enemies, such as the first game's Rippers, and making use of them as platforms before they thaw. It appears in most games.
  • Metroid Fusion: Samus uses Ice Missiles to freeze enemies, and needs to do so to progress at all after she gets the missiles.
  • Metroid Dread: Samus can freeze enemies with Ice Missiles, and only certain enemies can be used as platforms when frozen, like Sunnaps, instead of dealing Collision Damage.
• Fungus Humongous:
  • Found in a few corridors of Crateria in Super Metroid, yet noticeably absent in Brinstar.
  • The Phazon-irradiated mushrooms in Prime's Phazon Mines. They're big enough to use as platforms and solid enough to take a blast from a super missile. They're apparently being considered as a food source by the pirates.
  • Mushrooms also appear near the entrance to Tourian in Zero Mission, which is in a section of Brinstar similar to Super's "green" zone, but otherwise still rocky.
• Galactic Superpower: The Galactic Federation, which holds authority over hundreds of populated worlds and is the dominant governing & military force in the galaxy.
• Game Changer: Metroid: Zero Mission: Samus destroys Mother Brain and blows up the Space Pirate's base on Zebes, just as she did in the original game. Then pirate ships ambush her starship and send her crashing back down to the surface, now without a suit, weaponless, and with little hope of escape.
• Game Mod: Super Metroid has several. Of the complete overhauls of the game, amongst the best are probably Super Metroid Redesign, Golden Dawn, Super Metroid Dependence, Super Metroid Limit, and Metroid Legacy. Other good ones include One Room, T-Metroid, Magma, and Reverse. Of these hacks, Metroid Legacy is by far the easiest, being only negligibly more difficult than the original game (there are a couple of segments that require the use of "glitches" like the mockball and the wall jump, but by and large there is very little trickery required to complete it). Golden Dawn is somewhat more difficult, but still not that difficult. Most of the others are at the very least Nintendo Hard and often descend gleefully into Platform Hell territory. Redesign, for example, has a segment where you are required to go into the toxic regions of Norfair without the Varia Suit, and must progress rapidly and kill enemies in order to survive. (There is a way to get the Varia Suit before this with Sequence Breaking, but the sequence break is probably even more difficult). Worth special mention is Super Metroid Impossible, a "slight" overhaul of the original game that, thanks to the withholding of crucial items and strategic placement of obstacles, brings it up to Kaizo Mario World levels of difficulty. It is also worth noting that, while most of these hacks are roughly equal in size to the original game, Redesign is absolutely gigantic, being maybe three times the size of the original game. Redesign is also unique among Super Metroid hacks for significantly altering the original game's physics, which makes playing it a significantly different experience from playing any other Metroid game.
• Genius Bruiser: Samus and Ridley in addition to being twenty different flavors of bad ass. The character page has more.
• Ghost Ship: Literally, with the GFS Valhalla from Prime 3, the Wrecked Ship from Super with the ghost-boss Phantoon, and the Bottle Ship from Other M to a lesser extent. Though this one is played more straight in the epilogue, when it gets taken over by Phantoon himself.
• Go for the Eye:
  • Unlike in prior games, Mother Brain in Zero Mission can only be damaged with Missiles to the eye.
  • The Grapple Guardian in Echoes has to be shot in the eye in its second phase, mainly to make it lower its shield.
• Good Policing, Evil Policing: A plot thread of later games is that there's a corrupt faction within the Galactic Federation (who Samus works with, and was once a member of). Contrasted with Samus herself (an umambiguously heroic bounty hunter^note Which is canonically a title for people who freelance for the GF), and the more reasonable troopers and officials Samus works with or for. The English dub of some games muddied this a little by not making it clear that it was only one branch, and gave the impression the entire organisation was corrupt.
• Grandfather Clause:
  • Even in several Metroid games released long after the original, Samus' missiles tend to cap out at 255, despite that number only arising due to hardware limitations in the original game^note The maximum number of missile expansions actually ended at 230, but the password system could be tweaked to push it to 255. (Later Zelda games quickly did away with the 255 money Cap, for example) It's just always been a part of the series, and let's face it, any more would make 100% Completion even more insane than it already is, never mind how unbalanced it could make the game.
  • Samus' Morph Ball form also came about because of the hardware limitations making the developers unable to get Samus to crouch or crawl. Needless to say that these days, we have the technology, and yet the Morph Ball remains regardless. Its sheer versatility versus regular crawling may be why.
  • Among Americans at least, Metroid is considered one of the Big Three Nintendo franchises (along with Mario and Zelda). Part of this is due to the fact that all three debuted around the same time on the NES. Even though other franchises such as Pokemon or Kirby sell more, Metroid's recognition and historical position among American gamers means that the series continues to hold this status.
• Grappling-Hook Pistol: Grapple Beam.
• Gratuitous Japanese: "Maru Mari" means something akin to "round ball". It's the only item in the original Metroid to keep its Japanese name in some translated releases.
• Gravity Is Purple: The Gravity Suit, a recurring upgrade for Samus, is purple-colored in most games (The Prime games make it more bluish gray). However, a more literal example of this trope is in Other M, where the Gravity Suit is just a feature of the Varia Suit instead of its own thing. Activating it causes Samus to be surrounded by a purple aura, rendering her immune to all gravitational effects. In addition, in Other M, passages with strong gravity have dark purple walls.
• The Great Exterminator: Samus is Famed In-Story for her crusades in wiping out the eponymous species. She is specifically called in Galactic Federation thanks to this reputation.
• Greek Letter Ranks: The Metroid aliens metamorphose through 'stages', not unlike butterflies. From weakest to strongest, the stages are: infant, larval, alpha, gamma, zeta, omega, queen.
• Guide Dang It!:
  • 100% Completion is HARD. Especially in the original and II.
  • Fusion, Zero Mission, and Prime 3 really cut you breaks on this. At a certain point in Prime 3, you can launch exploration probes to the various planets you visit. These probes will report back every collectible you have yet to pick up. There are still a handful of items that reside on a derelict ship that you absolutely need to find yourself but otherwise, it is within reason for everyone who plays the game to get 100% without consulting a third party source. Not present on the first playthroughs, but Fusion and Zero Mission will have a timer and an item checklist for each area if you resume play on a completed file, or start a new game off of the same slot.
• Hailfire Peaks: Every zone in Fusion is "X meets Eternal Engine". The original and Super have a lot of "Underground Level meets X". Corruption has Bryyo, which has areas themed around Death Mountain, The Hedgeof Thorns, Lethal Lava Land and Slippy-Slidey Ice World respectively.
• Half-Human Hybrid: Samus is a genetically augmented human with Chozo DNA, and then later receives an anti-X "vaccine" made from Metroid cells, which allows her to eat the X as if she were a Metroid.
• Happily Adopted: Samus considers the Chozo her "real" family as much as anything, and they certainly don't skimp on the love. Fans who'd grown to associate Samus with this trope were understandably peeved when in Other M Samus refers to Adam as "the only father figure she'd ever known".
• Hard Levels, Easy Bosses: Zero Mission has this on Normal. The final boss gets significantly more challenging if you've got 100% completion, but by that point, you're so armed to the teeth anyways, it barely matters.
• He Who Fights Monsters:
  • Samus nearly succumbs to this in the third chapter of the manga. On the planet of Jigrad, she saves a group of slaves from the Space Pirates. When confronted by Samus, the last remaining Space Pirate pleads with her to show mercy. Driven by her memories of her homeworld K-2L being mercilessly razed by the Space Pirates, Samus is about to murder the last Space Pirate in cold blood when the sound of a small girl crying snaps her out of her rage. Shortly thereafter, the small child thanks Samus for saving her, and Samus tells her that she saved her as well from becoming just as much of a merciless killer as the Space Pirates. Also, Samus begins to physically, not mentally, resemble Dark Samus as Prime 3 goes on. A non standard Game over has her playing it straight though.
  • In Metroid II, Samus is charged with the task of eradicating the Metroids once and for all. After destroying the Metroid Queen, Samus finds a newly hatched Metroid. Despite knowing that Metroid is a Chozo word for "ultimate warrior", she refuses to kill a newborn child like Ridley would have done to her years prior. Fitting, then, that in Samus Returns Ridley happens to turn up as she's about to leave.
• Heart Container: Energy Tanks (represented on the HUD by a colored shape near Samus's Energy meter) are a collectible item that grants Samus 100 extra health on top of the stock 99 Energy that the Power Suit starts with (though they don't visually increase the number above 99, instead refilling the health meter when it goes below 0).
• Heel Realization: The eponymous Super Metroid has one just before it drains all of Samus' energy when it recognizes who she is: the "mother" it imprinted on when it was Baby Metroid she'd spared in the previous game.
• Heinousness Retcon:
  • Ridley started as one of the many Space Pirates bosses of the original games, and this remained unchanged for a time. There wasn't any connection between him and Samus. However, due partially to his popularity as his role expanded two adaptations rewrote him to give him a much more personal connection:
  • Metroid Fusion: The Japanese exclusive child mode was the first to show Ridley leading the Space Pirate raid that destroyed Samus' home planet and leaving her an orphan.
  • Metroid (Manga): Building upon the first example specifically has Ridley murdering Samus's mother, and was the cause of her father's sacrifice. Not only that, many years later Ridley kills Gray Voice, Samus's adoptive parent. The manga is stated as canon, thus later installations such as Metroid: Other M and Super Smash Bros. Ultimate would openly acknowledge Ridley as responsible for leaving Samus an orphan and killing her parents, giving them a deep connection for their enmity.
    Pit: So what's the story behind him and Samus?
    Palutena: Ridley killed Samus's parents when she was young.
    Pit: That's messed up!
• Heroic Mime: In Prime 3, the first voice-acted game in the series, she has no voice acting beyond her usual grunts, on the grounds that Samus talking would be "too creepy." In Fusion, she monologues a lot, and converses with her computer towards the end. She also does some narration in Zero Mission and Super, but only the very beginning of each game. Averted as well in Other M.
• Heroic Sacrifice:
  • Samus almost attempts one in Fusion by detonating the self-destruct charges on BS-L to destroy the X-Parasites aboard; herself included. The AI Adam, however, informs her that doing that would be stupid, as it would not destroy the X on Planet SR388, and only serve to destroy the X's greatest obstacle: Samus. Adam then promptly makes a Heel–Face Turn and decides to help Samus, making a different plan, which destroys all the X in both locations and allows Samus time enough to escape the station.
  • Also Adam Malkovich in Other M and the Metroid hatchling in Super Metroid.
  • Both of Samus' parents sacrifice themselves as well. Her mother does to save Samus, and her father sacrifices himself blowing up the Space Pirates vessel, along with most of their force. Ridley later taunts Samus by revealing that without a ship, he consumed the bodies of the dead humans to stay alive. Including her mother.
• He Was Right There All Along:
  • Acid Worm in Zero Mission, Elephant Bird and Yakuza in Fusion, Torizo in Super, Arachnus in Metroid II (averted in AM2R and Samus Returns)...
  • Averted with Ridley in Zero Mission. He was not even near the planet when Kraid was defeated, only just landing on it when Samus reaches his hideout, and not arriving in his boss room until just as Samus was about to leave with the Gravity Suit.
  • In Super Metroid, Ridley plays this straight, for both encounters.
• Hoist by His Own Petard:
  • Mother Brain attempts to finish off Samus with the Hyper Beam at the end of Super Metroid. Before dying, the infant Metroid steals it from her and gives it to Samus...
  • Zero Mission reveals that the reason Tourian is devoid of Space Pirates is because the Metroids they were producing got loose and killed them all. This is the usual result of people trying to use Metroids. One would think the Federation would have noticed this, but apparently the Ringleaders either didn't notice or didn't care.
• Hopeless Boss Fight:
  • The first fight against Ridley in Super; you can sort of win, as he fumbles the hatchling if you hit him enough times, but he still takes off with it after.
  • The Super Metroid Final Boss, which can only be won AFTER the Super Metroid's death — and yes, it's possible to fumble it and LOSE during this fight. And SA-X before Metroid Fusion's finale. And the Giant Metroid in Super Metroid.
• The Horde: The Space Pirate Confederation. A smaller but more competent example are The Ing Horde.
• Hub Level: The Main Deck in Fusion and the Temple grounds in Metroid Prime 2: Echoes.
• An Ice Person: Samus, considering all the ice power-ups. She gets this affinity turned around on her in Metroid Fusion; because she has Metroid DNA, cold becomes her greatest weakness. The organism in her old suit, the SA-X, uses her old Ice Beam to devastating effect whenever she bumps into Samus.
• Iconic Outfit:
  • Metroid II introduced the round-shouldered styling of her Power Suit to make the Varia Suit upgrade more readily identifiable with the greyscale graphics, and then Super Metroid made it the enduring look for her, such that it's her default suit appearance in the majority of her guest appearances in other Nintendo games.
  • The form-fitting Zero Suit under-armor Samus wears was first introduced in Zero Mission, and then the portrayal of Zero Suit Samus in Super Smash Bros. Brawl made it replace her previous under-armor clothing and jumpsuits in the public consciousness.
• Imprinting: One of the series' iconic scenes is at the end of Metroid II, where a Metroid hatches and imprints on Samus as its mother (and Samus is at least merciful enough to not kill it). The plots of Super, Fusion, and Other M all refer back to this scene.
• In Case of Boss Fight, Break Glass: ... well, how else are you going to Attack Mother Brain's Brain?
• Informed Ability: Zigzagged with one specific detail throughout the franchise: the Metroid II: Return of Samus manual specified that Samus's helmet has an "Infrared Ray Scope" that allows her to see in the dark, implying it's a standard feature. But this has been very inconsistent throughout the franchise:
  • Metroid II: Return of Samus: Even though the very manual tells you that you have night vision, there are pitch black rooms in SR388 where you will have to wander around blindly.
  • Super Metroid: Dark rooms are also pitch black, implying she can't see in them.
  • Metroid Fusion: When Samus enters the nocturnal Sector 6, there is a small light circle around her and dimmer surroundings, implying she does have some form of limited night vision ability.
  • Metroid Prime: This would become a gameplay element with the Thermal Visor that does allow for adequate vision in dark areas, except for the fact that Samus has to steal it from a Space Pirate lab as her base suit never had this ability, so it's not standard.
  • Metroid: Other M: The Geothermal Power Plant is shrouded in shadow until lava starts flowing into the room, once again showing Samus's night vision is limited.
  • Metroid Dread: The parts of Dairon that lack power at first arrival are very dark, yet again demonstrating a lack of night vision on Samus's part.
• Insectoid Aliens: The "Ki-Hunter" pirates of Super Metroid, Fusion, and Other M. The main space pirates seemed to be too but Prime revealed them to be reptilians in insectoid armor. Zero Mission pirates are not reptilian but still revealed what their heads look like under the helmet. The latter design was prominent in Prime 3.
• In-Series Nickname: To Space Pirates, Samus is "the Hunter" and Dark Samus is (only in Prime 2) "the Dark Hunter".
• Interquel: All of the games released after Fusion, starting with Prime 1, though their exact placement in the timeline varies.
• Interspecies Adoption: Samus was raised by the Chozo, who also taught her everything she knows as a bounty hunter.
• Introduced Species Calamity: The titular creatures are considered to be a dangerous threat to whatever environment (barring cold temperatures) they appear in, being near-unstoppable while consuming the life force of all organisms in their path. Despite this, Metroids are extremely desired by both the Space Pirates and the Galactic Federation for their potential applications, even if it means risking the lives of many to get their hands on even a single one. It is because of these factors that Samus is ordered to wipe out all Metroids from existence lest they fall into the wrong hands and become an invasive species throughout the galaxy. However, it turns out the Metroids were created by the Chozo to combat an even bigger threat to the galaxy known as the X-Parasites.
• It's Personal: Just read the manga and you'll see that Samus has quite the bone to pick with the Space Pirates, Ridley, and Mother Brain.
• Joker Immunity: The one time Samus finally kills Ridley in Super, he comes back, despite the fact a planet was blown up under his corpse's feet. Could be a justification for her Heroic BSoD in Other M. She thought he was Killed Off for Real and yet here he is, haunting her again.
• Kaizo Trap: Any Core-X that gives you Beam upgrades will shoot even if your hit kills it, so you can wind up being taken with it if you're low on energy, unless you time your dodge just right so it doesn't bounce off the outer shell because the Core-X turned to stay aligned with you. Or, you know, having more energy than the blast takes away, and using the Core-X to heal afterward.
• Kill Enemies to Open: The series uses these a lot, usually in the multiple pirate bases you'll have to raid. Also an egregious case of Fridge Logic, because unlocking the door for someone who has just murdered your security team seems like a genuinely awful idea...
• Kill It with Ice: The titular monsters, annoying as hell before you get some weapons effective against them. Though not as much with some of their later forms, the games rarely throw those at you.

L-Z

• Last of His Kind: Super Metroid features the last Metroid. Samus herself might even count, given that, although human, she's carrying the DNA of the practically-to-totally extinct Chozo race.
• Late-Arrival Spoiler:
  • The opening cutscene of Super Metroid spoils the endings of Metroid and Metroid II.
  • The ending of Super Metroid is spoiled in the opening cutscene of Other M. Then again, it's one of the most iconic games in the series, so odds are a new arrival looking up Metroid info has already stumbled across it on a message board or something anyway.
  • Samus being a girl was itself considered a plot twist at the beginning of the series, to the point where the original game's manual outright referred to her as male, in both the Japanese and English versions. At this point it's the only thing some people know about the series, and crossover media such as Super Smash Bros. don't even try to hide it. Hell, Zero Mission didn't bother hiding it, and it was a remake of the original game.
• Latex Space Suit: Zero Suit Samus.
• Lava Is Boiling Kool-Aid: In the original Metroid, lava was a red palette swap of acid.
• Leaning on the Fourth Wall: The Nintendo Power comic adaptation of Prime states at the end that Samus was only on Tallon IV for around 10 hours, which is around the time that a skilled player can beat the game.
• Left Hanging: Some people were a bit annoyed at the lack of a sequel to Fusion for over 19 years, in no small part because the ending to that game addressed but didn't resolve a little factoid: Samus just blew the shit out of a Federation-owned scientific laboratory, taking a planet and an illegal Metroid cloning project with it. Sure, Samus was getting rid of the new clone Metroids and the X parasites all in one go, but a secret faction within the Federation wanted to keep both of those around so they could use 'em as weapons... meaning that Samus is, in all likelihood, an outlaw now. The prequel, Other M, also deals with a rogue faction (which may be the same group as in Fusion), but it's still otherwise undeveloped beyond the possible inclusion of a Colonel, a scientist, and a now-dead soldier in their ranks.
• Legacy Boss Battle: Ridley, a Space Pirate pterodactyl/dragon-thing, has made an appearance for a boss fight in every game in the franchise except for five (out of fourteen).^note Metroid II: Return of Samus, Metroid Prime 2: Echoes, Metroid Prime Hunters, Metroid Prime: Federation Force, and Metroid Dread
• LEGO Genetics: Samus is a human being genetically enhanced by Chozo blood. By Fusion, she's also part-Metroid - although not as blatant as the trope normally implies. She doesn't change too much. Her immune system and body regulation have changed, but both could be justified. Still, Dread has the strengthening of the Metroid genes being a major plot point.
• Leitmotif:
  • Ridley, ever since Super, has had his own unique boss music based on one of the two boss battle themes used in Super (he originally shared it with Draygon and the Torizos). Depending on the game, a different remix of the theme will play in every battle with him. Even when fighting his adolescent form in Other M you can hear his classic theme stealthily incorporated, especially in the percussion. The song is also sometimes used as a self-destruct escape theme.
  • The SA-X has three distinctive tracks: one for when it's stalking a room, one for when it spots Samus and gives chase, and one for when the two finally throw down at the end of the game.
  • Samus herself has an entrance theme that was only ever replaced in Metroid II, though it makes a comeback in Samus Returns.
  • Brinstar has two themes that have become rather iconic in their own rights, despite not necessarily being the main theme of the game.
• Le Parkour: Samus in every game after Super, except Prime and that may count too because she still has awesome cutscene moves.
• Lethal Lava Land: Present in some form in every Metroid game except Echoes.
• Literally Shattered Lives: The traditional way to kill Metroids has been to freeze them with the Ice Beam and then shatter them with a missile. In Prime 1 and Echoes (with the functionally similar Dark Beam), this can also be done to many non-Metroid enemies. In Fusion, since Samus is part-Metroid now and the SA-X has all of your old gear, it does the same thing to you if it catches you.
• Living Gasbag: Many of the organisms float this way, including the titular Metroids.
• Living Structure Monster: The doors to a boss room in Super Metroid and Metroid Fusion are covered by giant eyes that shoot eyebeams at the player and must be destroyed before you can enter the room.
• Load-Bearing Boss: At least one in every game which will inevitably result in the destruction of a nearby planet (if not the planet under Samus' feet)...except Metroid II. At least, during the course of the game...
  • Metroid/Zero Mission: Mother Brain and Mecha-Ridley. In the latter case, Mecha-Ridley manually triggers the self-destruct sequence for the Pirate Mother Ship, wiping Chozodia off the map and allowing the Wrecked Ship to be explored in Super.
  • Prime: Parasite Queen and Metroid Prime.
  • Prime 2: Emperor Ing.
  • Prime 3: Every Seed boss and Aurora Unit 313.
  • Super: Mother Brain.
  • Other M: Phantoon (though, the timing is coincidental).
  • Fusion: SA-X (though, destroying it just removes the obstacle in the way of you doing the destruction).
  • Dread: Raven Beak (though this owes more to the ship collision that preceded the final blow).
• Lovecraft Lite: And does not become full on Cosmic Horror Story solely due to the presence of Samus, and in the case of Echoes and Hunters, it was a bonafide CHS before she came along. The galaxy always seems to be one instant away from destruction, and the destruction of one just leads to another, as seen with the Metroids and X Parasites. The Ancient Chozo foresaw many of these threats, but they are almost extinct today, and at least one of those threats wiped out a civilization that wasn't that much less advanced than them. It's fortunate that their last champion, an orphaned human who lost her parents to Space Pirates, is their greatest.
• Magitek
  • Both the tribals and the lords of science made use of mogenars during The Magic Versus Technology War. You can scan various remains of them and can't tell from the wreckage which ran on magic or mundane power.
  • The Aeion abilities seen in Samus Returns are said to be closer to magic than the other Power Suit functions, with the beam burst in particular resembling the charged hyper mode fire that had been achieved through mostly technological means.
• Malevolent Architecture: All over the franchise.
• Matter Replicator: Samus' Chozo-built suit seems to use this technology. It can turn into energy when not in use, can change back and forth from a spherical shape, and it has storage capacity for more missiles and bombs than the suit should physically be able to hold. In Fusion, upgrades for Samus' suit are sent to her as computer data and are downloaded into her suit.
• Meaningful Name: Both "Samus" and "Aran" have long been considered vaguely Irish in origin, Samus said to be a variant of Séamus (James)^note  A persistent myth seems to be that it's a real Irish name and the standard female variant of Séamus - it's not, as like English Irish doesn't have a female equivalent to James, or even a diminutive like "Jamie" in use as a woman's name., though eventually the developers revealed it actually comes from Pelé's real name, "Arantes" and the mistaken impression that his first name was something like "Samus"^note It's actually Edson - his full name is Edson Arantes do Nascimento. That said, "Séamus/James" is an offshoot of "Jacob", meaning "one who supplants/conquers/holds the heel" is actually surprisingly apt. The Aran islands are also three settled islands off the west coast of Ireland, giving you something akin to "She who supplants / isolated locations" (and the island imagery is fitting for such a loner hero).
• Mascot Villain: The Metroids that Samus Aran usually has to exterminate on a regular basis. They are also Mascot Mooks.
• Mechanistic Alien Culture: The Space Pirates.
• Metamorphosis Monster: While on their home planet at least, the Metroids go from floating parasitic jellyfish to beetlelike creatures to giant armored lizards. In an interesting twist, the first stage is not only the most well-known, but while nearly every game has a variant of the jellyfish stage, the later stages have only appeared in a handful of games. Metroid II originally implied that the Metroids were mutating, making them very different and more dangerous. It wasn't until later in the series that these "mutations" were retconned into being part of their natural life cycle, but which was only sustained in the correct environment (that of SR388). "Samus Returns" retcons it back, suggesting the metamorphosis beyond larva was unexpected by the Chozo living in peace with Metroids who no longer saw the Chozo as friends after reaching the alpha stage. Although "Returns" also suggests there was fighting between various Chozo factions that prevented the Metroid project from being truly completed...Whatever the case, the Federation still thinks Metroids "naturally" metamorphose on SR388, which is why Sector 1 (SRX) so seamlessly mimics the planet's environment.
• Metroidvania: The series started and codified the genre. It's in half of the trope name, too.
• Mini-Boss: Most games in the series include them in some way. Return of Samus depends on how the player interprets some of the enemies - Arachnus and tougher Metroid specimens might count, or they might just be bosses.
• Minus World: In the NES original and Game Boy sequel.
• Ms. Fanservice: Samus herself has a few showy moments every once in a while. If you were to beat the older games fast enough, Samus would not only take off the helmet, but also her suit, leaving herself in only a bikini. The newer games have the Zero Suit, which was pretty obviously created to accentuate Samus' curves.
• Multiple Endings: The Segmented Endings subtrope applies to the Prime series, Metroid 2, Super, and Other M; whether based on completion time, percentage, or both. Played somewhat straight with Fusion and Zero Mission's ending portraits.
• Mythology Gag: The final boss fight of Fusion. You get reduced to low health unfairly quick (no matter your remaining health prior to this), and then someone shows up to save your hide before you get finished off. That savior gets killed, Samus gets a new beam, and you beat the unholy tar out of whatever you were fighting. There are some discrepancies,^note Just to name a few: the Omega Metroid one-shots you while Mother Brain hits you hard over and over until you can't get up, the member of the Metroid race goes from being the savior to being the boss, Samus' Fusion Suit changes color but not the predecessor, Fusion's final battle is during the timed escape while Super's commences it, and the list goes on. but the similarities to Super Metroid are obvious.
• New Weapon Target Range:
  • Super Metroid:
    • The Hi-Jump Boots are located in a room that requires them to get out without Wall Jumping.
    • The Speed Booster is at the end of a long, sloping corridor that you need to quickly cross if you want to survive, and the game offers several sections to demonstrate that your ability can shred certain blocks and enemies.
    • The Grappling Beam is found in a room that is better escaped from by using the grapple points in the ceiling, followed by more rooms that are more easily crossed with the Grapple Beam featuring pits of water underneath in case you fall.
    • In the room where you acquire the Plasma Beam, you encounter Space Pirates that you may at least have difficulty damaging. Once you have it, killing them is easy even with an uncharged beam. This one is also Enforced, you must kill the Pirates because the door locks behind you and doesn't open until they're dead.
  • Metroid Fusion:
    • Acquiring Missiles is followed by a long section full of enemies and obstacles that can only be killed by missiles.
    • The Varia Suit is followed by a room full of Cold-X, all of which are now completely harmless to absorb, for your healing pleasure, especially if the Core-X didn't top you off.
    • The Space Jump is recovered in a large open room where you can practice jumping around to your heart's content.
    • You are given several Ki-Hunters to test your new Plasma Beam on after beating Nettori.
    • Shortly after acquiring the Screw Attack, you are given a chance to go nuts with it, in a room full of normally-invincible enemies, where you learn that the Screw Attack can destroy them with ease.
  • Metroid Prime:
    • The Space Jump Boots are followed by a short platforming section that leads you to the Chozo Ice Temple.
    • After acquiring the Thermal visor, all of the lights go out, requiring you to use said visor to navigate.
    • You find the Gravity Suit underwater. It immediately grants you better vision and the ability to move freely, and offers you a short platforming segment to prove it.
    • After getting the X-Ray Visor, you are forced to use said visor to escape the room, familiarizing yourself with it, as well as by setting several Chozo Ghosts on you, showing that now you can see them even when they go invisible.
    • After obtaining the Phazon Suit, you are forced to make your way through several regions full of the substance, demonstrating the new suit's protective capabilities.
• Nice Job Breaking It, Hero: When Samus eradicated the Metroids on SR388, her intention may have been to stop the Metroids from being used as a biological weapon ever again, but by removing an apex predator from the planet's ecosystem, the X Parasites that the Metroids preyed on were able to multiply unchecked. This sets up the events of Fusion, where the parasites become a potentially greater threat than the Metroids. Samus Returns includes this as part of The Stinger.
• Ninja Pirate Zombie Robot:
  • Ridley started as a dragon Space Pirate, and adds more to this title in the Prime games, culminating in him being a mutant cyborg dragon space pirate.
  • In Super, there are two gray Space Pirates that fight by using martial arts, which are called "Ninja Pirates" by fans to this day.
  • In Other M, there are melee cyborg Space Pirates (called Zebesians for some reason) with mind control units controlled by the Federation, making them a near literal example.
• Nintendo Hard:
  • The original game (and given the trope is named after the NES having abusively difficult games, it's not surprising in the least). Getting 100% without a guide is hard, doing that while beating it in under 2 hours is even harder.
  • The other games are easier due to gameplay refinements. But if this is you first time playing any particular game, be you a veteran or a newcomer, you WILL die at least 20 times. Now try and get 100% under 2 hours without dying on hard mode!
• No-Holds-Barred Beatdown:
  • Samus to Mother Brain during the mother of all Mama Bear moments at the end of Super Metroid. After what Mother Brain did, she completely deserved it.
  • Fusion sees this done twice, but the more pointed example is the Omega Metroid, as Samus is in a hurry and there's literally no strategy to killing it other than do as much damage as you can before that claw comes down, then get out of the way and move back in before it can step forward.
• No Hugging, No Kissing: The series has been devoid of romance since its inception. This is usually because Samus Aran's missions tend to only have her encountering the evil Space Pirates and various alien wildlife, but even the later games and supplementary manga and comics that do portray friendly, intelligent characters don't feature any romance. The only exception among the games is Metroid Prime 2: Echoes, where a Battle Couple are among the deceased Luminoth Keybearers.
• Noob Bridge: The Trope Namer is a crumbling bridge encountered early in Brinstar in Super Metroid, and the first place in the game that would require any player (of less than insanely good skill) to use the run button. The run button, however, is not part of a standard control scheme anywhere else within the Metroid series. Many newbies get stuck there, unaware of the otherwise obvious solution.
• No Transhumanism Allowed: One of the rare and surprising aversions: not only are cybernetics commonplace and carry no notable social stigma, Samus herself is a transgenic lifeform, with her adoptive Chozo caretakers having grafted their species' DNA onto her own to increase her adaptability to the harsh environment of Planet Zebes. Further, by Metroid Fusion, Samus is also part Metroid. And Adam (and many other political and scientific figures) regularly underwent Brain Uploading.
• Not the Intended Use: And not just in Sequence Breaking form either. Glitching Kraid in Super Metroid for instance, is not a sequence break, but certainly counts.
• Ominous Latin Chanting: Ridley's sub-sector of Norfair in Super, reimagined in Prime 1 as Magmoor Caverns and reused in Samus Returns for heated rooms. And it is AWESOME.
• One-Hit Polykill: The Plasma Beam works this way.
• One-Man Army: Both the Federation, and Samus all by herself, staged their own assaults on Zebes in the backstory of Zero Mission. The Federation failed. Samus didn't. And it's all thanks to you.
• Once per Episode: Every game features Samus living up to her Mike Nelson, Destroyer of Worlds status, with the ends of each game having her directly or indirectly causing the destruction of a massive, life-filled location following the defeat of the final boss, with the exception of Metroid II Return Of Samus and the demos.
• Opening a Can of Clones: Characters or creatures believed killed off in previous games commonly reappear as clones, robotic duplicates, X-Parasite doppelgangers, etc. (and in the case of Ridley, all of the above). This makes it almost impossible to truly believe that these characters are gone for good, and when some characters are revealed to survive (for example Kraid in Dread), there is a lot of speculation about whether it's the real character, a clone, or some other type of copy. There are even numerous theories that Samus herself is a clone, particularly following the events of Fusion.
• Opening the Sandbox:
  • Fusion and Other M are the most linear games in the series yet, and thus have very few opportunities to let you backtrack to earlier sectors on your own until the endgame.
  • Echoes is an in-between example as you usually can go back to any place you've been before, but it's more prudent to wait until either story progression takes you back there, or you've finished the area you were working on. The only optional Doors To Before were broken by Power Bombs while the path from the GFS Tyr's landing site to the Great Temple is explored backwards as your path to the elevator to Sanctuary Fortress. The sandbox is, however, only fully opened at the endgame.
• Palette Swap: As mentioned, lava was a palette swap for acid in the first game. It also had palette swaps of multiple enemies in a given area, with one color being tougher than another. The beam troopers in Prime are colored based on which beam hurts them. ^note They are said to be using inferior versions of your own beams, but only use the same one. Whether this was a bug, engine limitation, or intentional is unclear.
• Personal Space Invader: The titular Metroids, in their larval form, absorb energy from creatures by latching onto their heads.
• Pickup Hierarchy:
  • Primary: New powers, weapons and suits, Chozo Artifacts and Dark Temple Keys (Prime 1 & 2)
  • Secondary: Energy Tanks, Missile Tanks
  • Tertiary: Energy capsules and Missile ammo.
  • Extra: Energy cells (Prime 3).
• Pinball Spin-Off: Metroid Prime Pinball, which loosely retells the story of Prime 1 as a multi-table pinball game.
• The Pirates Who Don't Do Anything:
  • The Space Pirates themselves avert this. Samus is usually sent in to Pirate hideouts post-piracy. The Pirates steal the first discovered Metroid in the manual for both Zero Mission and the original game. You can see the Pirates in action in the opening sequence of Super Metroid, when Ridley steals the Baby from the research station. Presumably, pangalactic police prevent protracted piratical processes, only summoning up their favorite bounty hunter(s) to go in and blow up the place when they track down the actual lair, which would probably be largely immune to a head-on raid by Federation forces. The Pirates also did some pirating in Corruption, in which they hijacked an entire Federation battleship (the GFS Valhalla), murdered its entire crew, and stole its onboard Aurora Unit. Later, they tried to pull the same trick against the GFS Olympus. They didn't count on The Hunter being aboard, to say nothing about the other three hunters you'll be working with.
  • Samus herself plays it straight, as she doesn't do any "bounty-hunting" except in the first game/Zero Mission, Metroid II and in the prelude to Fusion (catching specimens from SR-388 for the Federation). Supposedly, Retro Studios wanted to add bounty-hunting side missions in Corruption, but this was vetoed by the higher-ups from Japan, who, rumor has it, thought it made Samus look like a criminal, having evidently never considered what "bounty hunter" means. This is averted in the manga, however: she specifically notes that she's charging for the bounty on one specific being.
• Plug 'n' Play Technology:
  • Samus' suit is described to be "modular", which means it can also identify other technologies and adapt them into itself. The suit is able to form new abilities just by absorbing "data" acquired from rooms and the DNA of the X parasites in Fusion. Hell, Space Pirate tech will work on it in some games.
  • Subverted in Zero Mission, where you find a few upgrades incompatible with your suit. You need the Fully-Powered Suit to use them. May be double subverted in that the suit you need is the one with Plug 'n' Play tech to begin with.
• Pocket Rocket Launcher: Samus' Arm Cannon is about the size of her forearm, but can swap between an energy beam gun and a rocket/missile launcher without changing size (well, except for opening up the muzzle). It can hold up to 255 rockets, if you find all the Missile Tanks. And fire the even bigger Super Missiles in games where they're separate missile weapons rather than a direct upgrade to basic rockets.
• Post-Defeat Explosion Chain: Defeated bosses are typically wracked by multiple small explosions all over their bodies before being destroyed.
• Posthumous Character: Adam Malkovich is long dead by the events of Fusion, though Samus monologues on having worked with him in the past and his Brain Uploading lives on as your Mission Control. Other M, which takes place before Fusion, shows his actual death to start the climax.
• Power Copying:
  • Starting with Prime and Fusion, Samus's Power Suit has displayed the ability to absorb traits of defeated foes, whether technological or biological in nature. It has become more and more common for Samus to gain an ability by defeating a boss with that ability, though the iconic Chozo statues holding upgrades remain common as well.
  • You regain your iconic abilities in Fusion by defeating X-clones of creatures that could utilize those abilities, like Arachnus with the Morph Ball and Serris with the Speed Booster.
  • To a lesser extent, the Sub-Guardian bosses in Prime 2, as they took less equipment due to you having less to lose in the first place. At least they left the Charge Beam and Morph Ball.
  • In Dread, each of the E.M.M.I. have an ability that Samus copies from their remains after destroying them. It's unclear whether the E.M.M.I. were provided with Samus's abilities or not... one character claims that the E.M.M.I. are capable of redesigning themselves (suggesting they developed those powers on their own), but that character is later established to have been deceiving Samus the whole game.
• Power Crystal: The Lensman-like hand crystal on the back of her left hand. Originally just a visual effect, Zero Mission made it integral to use of the Power Grip.
• Powered Armor: Samus' signature Power Suit.
• Prehistoric Animal Analogue:
  • Ridley, one of the main antagonists of the franchise, is a reptilian alien with a draconian and pterosaur-like appearance, possessing the crest and beak associated with Pteranodon.
  • Metroid: Other M has a recurring Mini-Boss enemy in the Pyrosphere that resembles a giant trilobite, even more so when it moves around by crawling. It is immune to Samus jumping on it and can only be killed by shooting a weak point on its underbelly when it lunges to attack.
• Private Military Contractor: What Samus actually is. Despite being referred to as a "bounty hunter" she doesn't actually take on bounties, most often serving this function to the Federation instead. The one game that actually considered a bounty system, Metroid Prime 3: Corruption, had the idea shot down by Nintendo themselves while it was still in pre-production.
• Puzzle Boss: Many, including Crocomire and Flaahgra.
• Puzzle Pan: All 3D games but Echoes especially. Sometimes accompanied by weather patterns or fauna movements to smack where you need to go over your head.
• Raised by Natives: Samus, though the Chozo WERE pretty tech-savvy.
• Rasputinian Death: Crocomire in Super Metroid.
• Real Life Writes the Plot: A variant. A lot of the series' conventions were established by attempts to work around programming and data limitations of the original NES. The Ice Beam, for example, boiled down to toggling the settings for "enemy doesn't move" and "Samus doesn't take Collision Damage", as a way to save space on platforms.
• Recurring Boss: SA-X in Fusion, though it's not really a boss until near the end of the game. Ridley may be a better example, considering he appears in almost every game, twice in Super and Corruption. Also, The final boss and title antagonist of Metroid Prime comes back as Dark Samus for the second and third games of the trilogy.
• Recurring Element: Samus shattering a glass tube with a Power Bomb has appeared in six games of the series, starting with Super.
  • In Super, breaking a Shark Tunnel yourself is how you can shortcut into Maridia.
  • In Fusion, smashing a tube is part of how you reach the Level 4 Security Room in Sector 4.
  • In Prime, the Ice Spreader in Magmoor Caverns is hidden below the Bendezium-reinforced glass tube in the Shore Tunnel.
  • In Zero Mission, destroying the glass walkway in the Space Pirate Mother Ship is how you leave Chozodia to return to the rest of Brinstar with the Legendary Power Suit.
  • In Echoes, Sanctuary Fortress has a shortcut elevator hidden down a path you reach by blowing up a tube.
  • In Dread, the final E.M.M.I. in Hanubia blows up a glass tube on you. Once you defeat them, you get to blow up one tube to get out of the E.M.M.I. Zone, and another to reach Itorash from the same location.
• The Reveal: In the original game, at the end the super-tough merc you've saved the galaxy with takes off his helmet and... he is a she. Yes, Samus Is a Girl. Now it's common knowledge.
• Ridiculously Cute Critter: In the manga, Samus' pet Pyonchi appears to be about half squirrel, half rabbit, and all adorable. Also, the Etecoons ^note monkey-koala hybrids and the Dachoras ^note ostrich-style creatures in Super and Fusion. Maybe the "little birdie" of Other M as well, at least until you learn it's actually Ridley's clone.
• Roar Before Beating: Some of the bosses do this.
• Roaring Rampage of Revenge:
  • In Super Metroid, Samus only hunts down the Space Pirates for stealing the Baby Metroid and destroying the space station she'd left it at.
  • Revenge on the Space Pirates could be seen as one of Samus' main motivations, especially against Ridley, who personally killed her mother right in front of her when she was three years old.
  • The last bits of Zero Mission: The defeat of Mother Brain is spoiled by Space Pirates shooting you down. And your suit is lost. Then you get a better one which is followed by the annihilation of every Space Pirate on the Mothership.
  • In Dread, Samus engages in an absolutely savage beatdown on the Final Boss, even screaming in sheer fury, as opposed to her usual quiet stoicism. This is largely because Raven Beak had been revealed to have indirectly caused the entire Metroid crisis, not to mention having deceived Samus for the whole game, sent a whole bunch of hunter-killer robots after her, and murdered Quiet Robe.
• Safely Secluded Science Center: A recurring motif in the Metroid series is that the eponymous Metroids are so dangerous and so sought-after that the Space Pirates and The Federation have to carefully store them in isolated and heavily fortified places, preferably where there's plenty of frigid cold. Examples include Mother Brain's fortress of Tourian (Metroid, Super Metroid, Metroid: Zero Mission), a laboratory amidst the frigid Phendrana Drifts (Metroid Prime), an isolated section of the floating Skytown (Metroid Prime 3: Corruption), and restricted labs hidden deep within space stations (Metroid Fusion, Metroid: Other M).
• Savage Setpiece: A turtle in a remote room in Maridia will become hostile if you attack its children. It rises into the air if Samus jumps onto the shell.
• Save Point: The second type is a common sight in the series. With the exception of Chozodia save points in Zero Mission and Samus' gunship, they never refill health or reload ammo. The Save Stations in the Prime series, however, save and heal, but don't reload your ammo.
• Scenery Gorn: Old Tourian in Super and post-Mother Brain Zero Mission, Sector 5 (ARC) in Metroid Fusion.
• Schematized Prop: Many of the later games have taken up this trope, most notably using a Power Suit schematic as the item/weapon status screen (Zero Mission, Prime, Prime 3, Super, Fusion; the schematized suit was also seen in the instruction manual for Metroid II, which labeled her Left Hand of all things).
• Science Fantasy: It tends to skew heavily towards the science side of things but there definite fantasy elements, first becoming apparent in the wrecked ship of Super Metroid and becoming even more obvious with the Metroid Prime games, that detailed what the Chozo were like, and it's even canonically referenced in Zero Mission with the penultimate boss being a spirit inhabiting some Chozo Ruins.
• Scifi Writers Have No Sense Of Scale: Very few of Samus's weapons have numbers behind them, but those that do are absurdly powerful, like "fully automatic five-packs-of-C4 launcher" powerful. And then there's the Power Bombs, which are basically environmentally-friendly nukes in that there's no fallout and whatever isn't meant to be destroyed is not.
• Screw the Rules, I'm Doing What's Right!:
  • In the 3rd chapter of the manga, Samus - a newly recruited Galactic Federation Police Officer - and two fellow officers Mauk and Kreatz, are sent to planet of Jigrad on a recon mission to monitor the Space Pirates' activities there. Finding the Pirates are using human children as slave labor, Samus jumps in and massacres the Pirates before they can execute a child for being "unfit" for labor instead of reporting the find and waiting for orders. She and her team are later scolded by Chief Hardy, but Samus is praised by the Jigradian people for her help.
  • The finale of Fusion has the Federation ordering Samus to stand down so that they can capture the SA-X for study (also Samus just blew up their top-secret Metroid cloning facility, so they're a bit ticked about that). Samus knows firsthand just how dangerous the SA-X is, so she proceeds to crash the space station into nearby planet SR388, destroying both and eradicating the X for good. Given how much the Federation had invested into that, the general thought among fans is that Samus is no longer on their good side after this.
  • This is actually Samus's motivation for staying on the Bottle Ship in Other M. Even though it's been cordoned off by the Federation, she's pretty sure Adam's team is going to die if she isn't there to protect them. Adam himself knows it too, but is too bitter to go along with it until she agrees to act as his subordinate.
• Sea Monster: The boss Serris is a sea serpent with Super-Speed. Before Serris, there was Super miniboss Botwoon, who was a serpent like Serris who sped up as he took damage, and could spit acid spread-shots. Also Draygon, the boss of Maridia.
• Sequel Hook:
  • Fusion sure seemed to leave one hell of a sequel hook, what with Samus having illegally blown up a Federation outpost and become something way other than human. Sure, Samus had her reasons, but all the implications in-game are that the Federation will be pissed at her now. A sequel on the DS with 2-D gameplay, Metroid Dread, was supposed to have been shown at E3 2006, but was mysteriously dropped. Potentially hinted at again in Corruption, however. It was finally confirmed in E3 2021 as a 2½D game.
  • Each of the Prime games shows one if the player gets 100% Completion. Even Federation Force.
• Sequence Breaking: The Metroid fandom coined this term from their extensive experience with this trope. The series is famous enough for this to have its own subpage for it.
• Sequential Boss:
  • The final boss of Metroid Prime has two phases: the first phase is basically the same thing with increasing shifts to different weaknesses, and the second phase requires you to switch visors to locate the phasing Prime and blast it with the Phazon Beam.
  • The final boss of Metroid Prime 2: Echoes features all three forms of the Emperor Ing, followed by a final battle against Dark Samus.
  • In Metroid Prime 3: Corruption, you fight Aurora 313 right after putting down Dark Samus. 313 itself has two forms: complete and floating severed head.
  • Mother Brain from Super Metroid has 3 different phases. First you fight her like in the first game, as just the brain protected by turrets and zeebetite barriers. After you beat her and examine the body, she rises out of the floor on a robotic body. After dealing enough damage to her, she'll use an extremely powerful attack to reduce you to low health, after which the Metroid hatchling shows up to save the day. But then she comes back to life again and you have to beat the crap out of her again, this time armed with the Hyper Beam. And then you have to escape the planet before it blows up.
  • Metroid Fusion has the SA-X when you finally get to fight it. First there's the regular Varia Suit-sized version you've been avoiding the entire time. Hit that with your charged up Wave Beam, and you get a giant monstrosity that can't shoot you but can somehow jump anywhere in the room incredibly fast... Fortunately it stands still for a second every now and then and Screw Attack does work too (although it's a double-edged sword since it also hurts yourself...).
• Shapeshifter Baggage: Samus herself with the Morph Ball but the shape shifting is not actually the worst thing about it (the issue of vision is) nor is it the most glaring example; that goes to the X Parasites. They not only multiply impossibly fast but they can take on new, often large, forms nearly instantly, much to the frustration of many players.
• Shark Tunnel: These are a common feature, starting with the tunnel between Brinstar and Maridia in Super Metroid, to the underwater tunnel in Sector 4 in Fusion, the skywalk between Chozodia and the Pirate Mothership in Zero Mission, and the skywalk from Magmoor to Phazon Mines in Prime. All of them can be shattered with power bombs to allow free travel between the two areas.
• Shifting Sand Land: Sector 3 (PYR) in Fusion, the Agon Wastes in Echoes, and the Experimental Simulated Desert in Other M. Super has a section of Maridia, but not to the same extent as the other three.
• Shout-Out:
  • Several to the Alien franchise. Ridley is named after director Ridley Scott, and the opening shot of Prime is almost identical to that of the first film. Even the title logos have similarities (ALIEN - メトロイド).
  • A non-enemy creature in Super Metroid has a turtle like shell that flies around while spinning. Likely a nod to Gamera. Or possibly Bowser. Its offspring look strikingly similar to Buzzy Beetles.
  • A blink-and-you'll-miss-it example is the name of the planet that houses a Federation shipyard, where the GFS Olympus and two of Samus' gunships (the ones used in Prime 2 and Prime 3; she goes through gunships like other people go through tissues) were built: Aliehs III.
  • And then there's the fact that, as of Super Metroid, Samus can SHIIIIINESPAAAAAAAARK!
  • Houston from the Super Metroid Comic in Nintendo Power seems to refer to Captain Dallas from the first Alien film.
  • The original Famicom Disk System version of the first game's Escape theme and subsequent arrangements in future games don't have it, but the NES version features a slight expansion that includes a recurring six-note melody from the Kid Icarus (1986) soundtrack.
  • Moonwalking in Super Metroid, though only the name is a reference, it was just Samus slowly walking backwards, no illusion of walking forward involved.
  • The Restricted Area in Fusion looks and acts a hell of a lot like Tourian.
  • Outside the actual series, in Super Smash Bros. Brawl, one of Zero Suit Samus' air-attacks is the Inazuma Kick from GunBuster.
  • In the Wanpakku manga/strategy guide for the original game, there's a sequence where Samus comes across a door for the first time, but doesn't know how to open it. She tries saying "Open Sesame!", followed by "Bamble, bomble, bambopp!" and "Pastel, popple, poppinpa!". (Neither of them worked.) The latter two phrases are incantations from Magical Girl shows (specifically Creamy Mami, the Magic Angel and Magical Idol Pastel Yumi, respectfully).
  • The Zero Suit is one to the datasuit of Appleseed that Deunan wears in her landmate. More references can be found in Other M, with Samus's teenage design strongly resembling Deunan and she even has the same Japanese voice actress that played Deunan in the 2004 movie and Appleseed: Ex Machina.
  • The mentioned in Metroid Prime 3: Corruption "Horus Rebellion" is a reference to the "Horus Heresy" event from Warhammer 40,000, another rebellion that was indeed some "nasty business," enough to cause a schism within the Imperium of Man. Said rebellion was led by the eponymous Horus, who was corrupted by the Chaos Gods, much like how Dark Samus in this game brainwashes the Space Pirates for her own ends. Coincidentally one of the daemons from early in Warhammer was named "Samus".
• Slippy-Slidey Ice World: Sector 5 (ARC) in Fusion, the Cryosphere in Other M, and the Phendrana Drifts in Prime. Bryyo Ice in Prime 3 just barely makes it.
• Sole Survivor:
  • Samus, twice over: first when the K-2L colony was slaughtered by the Space Pirates, and again when the Space Pirates, under Mother Brain's direction, invaded Zebes and killed the remaining Chozo. Well, on Zebes, anyway. And then there's the last remaining Metroid from Metroid II.
  • The only Space Pirate who actually survived Super Metroid without being cloned or remade was Phantoon.
• Something Only They Would Say:
  • How Samus discovers the identity of her AI CO in Metroid Fusion.
  • Many fans realized what the mysterious trailer for Other M was as soon as Adam said "Any objections, lady?" Prior to this, it was intentionally unclear what the game in question was.
• Sound of No Damage: In the 2D games, it sounds something like a beep, but may in fact be more like a ding.
• Space Isolation Horror: Deliberately, the entire franchise is an example of this trope. The developers of the first game stated that it was their intention to make the player feel trapped and alone in a very hostile and alien world. The visuals and audio work to built the atmosphere of isolation.
• Space Marine: Introduced in the Prime games as the Galactic Federation Marine Corps (GFMC), while the Federation Army was first mentioned in the Zero Mission manual and properly introduced in Other M on-screen for the first time. Both are capable, just not as good as Samus. Subverted in all the Japanese text of the franchise, which only indicates the Army exists: there is no mention of any Marine Corps in the Japanese versions of the games.
• Space Pirates: The primary antagonists for most of the series, though the name is a bit of a misnomer, being that they are an multispecies alien army that performs piracy incidentally as part of their larger goal of interstellar conquest. They are the main villains in almost every game up to Super Metroid timeline-wise, and still manage to make minor appearances even in the games where they aren't. Out of 14 games in the franchise, the only game that does not have a single Space Pirate in it is Metroid II: Return of Samus and even then, its remake Samus Returns adds in Ridley as its final boss battle.
• Space Police: The first armed organization formed by the Galactic Federation to deal specifically with the threat of the Space Pirates, known as the "Federation Police." Despite the name, the Police are actually closer to military police or a gendarmerie as opposed to the popular image of a civilian beat cop^note interestingly, this was how the first game's manual depicted the police, as a sort of space cop with a badge: Both the Metroid II manual and the Samus Returns intro cutscene refer to Federation Police personnel as "soldiers," and a panel in the manga also shows them wearing military-style fatigues/camouflage while on a mission to capture a local Pirate leader. In the manga after she left the Chozo's care, Samus herself served in the Federation Police and became part of an elite squad (also shown in the Captain N comic) before she resigned to become an independent bounty hunter. This aspect of Samus's backstory is only from these two sources and is likely non-canonical according to the games, as both Other M and Dread mention only a previous service history in the Federation Army for her.
• Species Title: Named after a species of biologically engineered Life Drinkers that Samus Aran must frequently wipe off of various planets to keep them from being used as bioweapons by the Space Pirates.
• Speedrun Reward: In addition to your completion percentage, how fast you beat the game may factor into the ending in some way or another.
• Spin Attack: The Screw Attack has Samus leap in a spinning ball to attack her foes.
• Sprint Shoes: Speed Booster. Full stop.
• Star Fish Aliens: The main ones are X Parasites, the Ing, and Metroids, but others tend to pop up.
• Statuesque Stunner: Samus. Gandrayda is even taller.
• Steam Vent Obstacle:
  • In the intro level for Super Metroid, Samus needs to escape a space station, while avoiding gushes of steam coming out from practically everywhere. Getting hit by the steam doesn't cost you energy, but you lose precious time to escape.
  • Happens again during the escape from planet Zebes, only the steam's escaping from the ground itself.
• Story Arc: The chronology of the series is divided into four arcs: The original story where Samus storms the base of the Space Pirates in Zebes (Metroid / Zero Mission), the Phazon incident (the Metroid Prime Trilogy sub-series), the story where Samus has to exterminate all Metroids except the one she spared and then rescue it from the Pirates (Return of Samus / Samus Returns and Super Metroid), and the story telling the consequences of the Metroids' near-extinction plus the dubious ethics of the Galactic Federation and even those of the Chozo (Other M, Fusion and Dread).
• Suddenly Blonde: In the original game, the Samus unmasked sprites gave her brown eyes, reddish brown hair, and a pink leotard (or bikini for the quick players). Come Super Metroid, Samus is blue/green eyed, blonde, and is wearing a dark blue leotard.
• Suddenly Voiced: In Super Smash Bros. Brawl, Samus finally spoke her taunts. However, they sounded... odd. In Other M, she speaks for the first time in her own series. (There were previously plans to have voiced narration from Samus in Metroid Prime, but said narration was removed, leaving Samus with no voice lines for that game.) She also gets voice acting in Metroid Dread, but she has only one line, and it's in Chozo.
• Superweapon Surprise: Don't mess with Chozo statues... just, don't. As Meta Ridley found out the hard way in Prime 1's endgame: "Those who defile [our statues] shall know our wrath, unfettered and raw." And do you know what you get when the peaceful, spiritual race bird race actually trains someone to fight, and gives them the technology to do so? You get Samus Aran.
• Suspicious Videogame Generosity: If there is a save station, and possibly a recharge room too, near a big room, expect the big room to have a boss in it. Sometimes not the case, but usually there's one nearby.
• Swiss-Army Weapon: Samus' cannon shoots various beams, including power, ice, plasma, and wave, and also missiles. The whole power suit kind of qualifies.
• Sympathy for the Devil:
  • As the series goes on, you realize the Metroids aren't so bad — this culminates with Samus becoming part-Metroid in Fusion.
  • In Other M, MB when you know her past and the reason of her rampage.
• Theme Music Power-Up: This occurs in nearly every game, but perhaps the most gratifying moment is in Zero Mission when, after running for your life from Space Pirates with nothing but your "Paralyzer" Emergency Pistol and overcoming the Chozo Ruins Test, Samus' unknown items transform into the Plasma Beam, Gravity Suit, and Space Jump. At this point, you can finally kill the Space Pirates... with cathartic ease.
• Tomato Surprise: Has reached It Was His Sled status for common knowledge that Samus Is a Girl.
• Took a Level in Badass:
  • In Super Metroid, Samus' surrogate Metroid child returns. It's gone from tiny to around four times as big as Samus. It later holds off Mother Brain.
  • In most games, the Ice Beam is a useful weapon, but not that powerful. In Fusion, Samus develops a weakness to cold and loses the Ice Beam. It becomes a weapon of pure murder when used against her, and it's the last weapon she gets in the game.
• Trauma-Induced Amnesia: Happens to Samus in the manga. The trauma of watching her homeworld being destroyed and watching her parents die is essentially forgotten until Ridley forces Samus to remember what happened in their first encounter many years later. After remembering the event, Samus suffers a horrendous Heroic BSoD and begs her comrades to kill her. She gets better, thankfully, and THEN she kicks Ridley's ass.
• Ultimate Life Form: Metroids are energy parasites. They can mitotically divide when exposed to certain radiations and as they grow they alter their physiology. They were artificially created by the Chozo, and metroid is actually a Chozo word that means "ultimate warrior."
• The Undead: Coverns (Three skulls stuck together), Phantoon (Huge malevolent spirit allied with the Pirates), Chozo Ghosts, Dark Troopers, and Skeleton Crocomire.
• Underground Level: A prolific area type within the series. The first three games take place almost entirely deep within the bowels of alien planets, though Metroid II and Super Metroid do feature some ground-level locales, as well.
• Underground Monkey: A form of the trope is used with deceptive frequency in the early installments, which have multiple sets of enemies that function close to, if not identically to one another despite having distinct appearances.
• Unique Enemy: Used frequently beginning with, and especially in, Super Metroid.
• Vague Hit Points: Enemies usually die in a few hits, so Hit Points don't have to be indicated, starting from Metroid.
• The Very Definitely Final Dungeon: The Final Boss is always in an impressive location:
  • The original puts Samus in Mother Brain's subterranean lair, where you fight the Metroids for the first time.
  • Metroid II has the nest of the Metroid Queen.
  • Super Metroid takes us even deeper into planet Zebes, to fight Mother Brain again.
  • Fusion ends things Where It All Began: the final boss is faced in the docking bay.
  • Prime ends in an impact crater from a Phazon meteor.
  • Zero Mission has Samus infiltrate the pirate mothership.
  • Echoes has the Sky Temple, where the Climax Boss is fought, and its gateway, where the True Final Boss is fought.
  • Hunters gives us the Oubliette, a ship constructed for one purpose: to house an Eldritch Abomination.
  • Corruption ends on a sentient planet.
  • Other M brings a cloned Metroid Queen back for a showdown in a secure room aboard the Bottle Ship. At the end of the epilogue, Phantoon is fought in a giant, wide open room with glass Phantoon attacks from.
  • Federation Force ends on a giant Space Pirate superweapon called DOOMSEYE (all-caps included). It's a Metroid-style Death Star.
  • Dread's final boss battle is in Itorash, on the main bridge of Raven Beak's command ship floating high in the skies of ZDR.
• Victor Gains Loser's Powers:
  • Samus in Metroid Fusion had all her abilities copied by X. After killing X-infected bosses (which tend to be able to produce similar attacks), she can absorb the X parasite to regain that power. Averted with Missiles and Bombs, which are downloaded via the datapack that replaced Samus' jetpack.
  • In Prime, the Phazon Suit is received after the defeated Phazon-charged Omega Pirate collapses on top of Samus.
  • Echoes has Samus lose most of her starting abilities to a mob of Ing, and subsequently regain them after prevailing in one-on-one boss battles where they're used against her.
  • Corruption has Samus gain the Ice Missiles, Plasma Beam, Grapple Voltage, and all the Phazon upgrades from defeated bosses.
• Video Game Remake: Zero Mission and Samus Returns.
• Villain-Based Franchise: Fusion more or less Inverts this, giving Samus herself Metroid-DNA.
• Villain Decay: The titular creatures are the scourge of the universe in Metroid and Super Metroid, needing to be frozen and pelted with missiles to kill. Through the Prime series, they become progressively less of an actual threat. In Prime 2, even their possessed and powered up forms can be beaten with enough firepower from any of your weapons, and in Prime 3, you eventually get the ability to kill Phazon Metroids by shooting through their nuclei. Until then, though they can turn into vapor... Possibly justified; the Metroids in the Prime games are a different strain (Tallon Metroids) that have been horribly mutated by massive, repeated exposure to Phazon. The "Natural" SR388 strains, on the other hand, are only vulnerable to cold until late in their life cycle.
• Wall Jump:
  • Starting with Super Metroid, Samus quickly became one of the most notable employers of this technique. It also is the primary tool of sequence breakers.
  • Prime 2 was the first game that explicitly informed the player that this was one of Samus' abilities; in all previous games, it was a secret, and admittedly optional, technique.
• Weird Weather: Acid rain is a recurring hazard on the surface areas of planets:
  • Super Metroid claims this is the rain seen at Crateria, even though Zero Mission sees Samus running through rain without her suit on...
  • In Metroid Prime 3: Corruption, it appears on the Space Pirate Homeworld. Unlike the first game, you need a specific acid-proof "hazard shield" item to protect Samus from it. The Space Pirates themselves seem immune to it.
• What Measure Is a Non-Human?: Averted in Metroid II. Samus couldn't bring herself to kill a child, even if said "child" was a parasitic monster and a potential threat to the galaxy. That "child" imprinted on Samus and beleived her to be its mother, which played a part in Samus' decision and she soon devloped an attachment to the creature.
• Wolverine Publicity: The Varia Suit is used in almost all of the series' covers and promotional images, even though it's typically only the middle of three suits.
• Womb Level:
  • The innards of the Leviathans in Prime 3, though that's more of a case of "Womb Boss Chamber". Phaaze is a living planet, too, though only a few parts of what we see of Phaaze is definitely organic.
  • The Impact Crater in Prime has teeth in one room.
• You Don't Look Like You:
  • Samus suffered this problem early on. First she had brown hair, then the NES Varia Suit turned it green, and Benjamin Itoh made her a purple-head. It wasn't until Super that she was finally cemented as a blonde. Plus, her various facial features and hairstyle fluctuated. However, once Zero Mission hit, her appearance seemed to standardize.
  • Her armor also changed drastically between Metroid 1 and 2, and all flashbacks to the first game depict the redesigned armor. It got a further redesign in Other M, which is also depicted in flashbacks to Metroid II and Super Metroid. As if that wasn't enough, flashbacks to her Army days use a suit similar to how it looked in Prime 1. And then it was redesigned again in Samus Returns, but it doesn't seem to have stuck, since Super Smash Bros. Ultimate re-used her Other M design.
• Your Princess Is in Another Castle!: You've defeated Mother Brain and escaped Zebes in Zero Mission... the game is over, right? Though, you never did find out what those mysterious power-ups were for... Your ship gets shot down and you must sneak through the Space Pirate mothership to get your suit back.
• Zeerust: It's not really apparent in-game, given the low graphical capabilities of the console and the general lack of technology aside from Samus' suit, the doors, and the elevators, but the artwork of Samus for the original NES game makes it very apparent that Metroid was made in The '80s. It has a rather boxier look than later portrayals, for one thing. Later games aged much better in this regard: even the immediate sequel to the first game, which was released only a few years later, features an artwork design for Samus that still looks pretty good even after twenty years.
• Zip Mode: Samus' Speed Booster could be considered this if you have to trek along a long straight path; she will travel fast enough to kill all normal enemies in the way, but only if you actually run in Super.

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The End
SEE YOU NEXT MISSION!

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