Robo-Shota - Robot Buddy Sasuke, thanks to his small stature, naiveté, and reputation as the perennial uke in the Japanese fandom. The maid costume he gets in Goemon's Great Adventure only makes things worse.
Reika is derogatorily called the "Hose Beast" in the only existing review and walkthrough, both written by Kristina Potts. Alternately, one could also call her "the Joker" because of her exaggerated lips.
B-Spec Bob: The B-spec (AI driver who drives for you) driver, which has no name when it debuted in Gran Turismo 4. In 5, the game assigns random name of the B-spec driver when it is created, which can be changed during this process only.
Jenkins: A cat in the Kyoto - Gion photomode location.
Noob Combo - The plasma pistol and battle rifle from Halo 2, two weapons which, together, were practically a Game Breaker. The pistol received a nerf in Halo 3 to undermine this.
Half-Jaw: The Shipmaster (named Rtas 'Vadum in the fluff), an Elite commander, named after the fact that he is missing two of the predatorish mandibles that Elites have.
Arby/Arbs - The Arbiter
Arbitur - M4stur Ch!3f (or some variant) of Arby Nthe Chief calls the Arbiter this. He's called him many things, of course, but this is the only one translatable from L33t Lingo I can think of.
Infection form flood◊ are commonly known as "bogies" or "boogers" by players. Also have been referred to as "heads," possibly because of the similarities the flood have with zombies (and the necessity of shooting "the heads" first.)
Carrier Flood have also been referred to as "Pods" or "Puffer Pods."
Popcorn can also apply to the infection and carrier forms.
"Gaylo Reacharound" for Halo: Reach, by either detractors to the series or fans looking to mock detractors to the series.
G-Man is on the borderlands on this trope since he is never called anything by the other characters in Half-Life and only mentioned as "Our mutual Friend" in Half-Life 2. However he is not acctually named by fans since the name G-Man is picked from the name of his chracter models in the game files. Still it was fans who started referring to him as G-Man.
Jack: The first, and previously most common, protagonist. He's called "Pete" several times in canon, but "Jack" took off due to the SNES "Jack and the Beanstock" styled scene. The name is used for most other male protagonists, despite them having their own names too.
Jill: The Another Wonderful Life protagonist. It goes with Jack's name. Her canon name is "Pony" but it's atypical sounding. Sometimes used to refer to Claire, the blond protagonist from Back to Nature For Girl.
Hansel and Gretel: The protagonists of Grand Bazaar
Phillip and Lillian: The protagonists of A Tale of Two Villages.
Jojos Bizarre Adventure All Star Battle is called "Grasshopper Game" in Japan, due to the fact that the majority of higher level fights revolve around both fighters hopping around the stage and hoping to either hit with an air move or knock the other out of the sky with a good anti-air. There's a reason why this game's tiers are built around having a good air and anti-air.
Journey used to have a glitch that generated an immobile scarf connected to the ground in the second to last area of the game. Those in the development team that knew about it called it "Gary the Scarf," which spread to the fans. At some point, a second scarf appeared near Gary and fans began calling it "Larry the Scarf." Sadly, a patch was eventually released that removed both Gary and Larry from the game.
The Sporking Bitch - Axel, due to his appearance in nearly all MSTs of Kingdom Hearts fanfiction.
Xaldouche - Xaldin, due to his Jerkass behavior in Days.
Zexy for Zexion, made up from his actual name and the word "Sexy." Fangirls tend to use variations of the phrase "Zexy is so sexy with his lexy" ("lexy" for lexicon, as in the book which he uses for a weapon).
This one was actually used in the original version of Chain of Memories, making it not so much a fan nickname as an actual nickname that caught on with the fanbase.
Incidentally, "Lexy" may also refer to Lexaeus, given the fact that they're consistently seen (and, thus, paired in the fandom) together whenever they're shown at all.
Or rather, when Lexeaus is shown at all, since he's the least Bishōnen of the Organization, while Zexion is unarguably the most.
Xarmy Use/Xarmy Sue: Xion, due to being yet another female Kingdom Hearts Character in loose relation to Kairi, who falls victim to the Common Mary Sue Traits. The fact that she's pretty Emo for most of the game though she's got her reasons, to say the least and ends up being a secondImplied Love Interest for Roxas, besides Namine, doesn't help.
Xomg/Gloomex: The Organization Moogle in 358/2 Days, due to the member's habits of rearranging their names with an "X."
Mooglex: A less creative variation of the above.
Somebodies: An unofficial name for the human forms of the members of Org. XIII, as opposed to Nobody.
However, in CoM, Axel says "We Nobodies can never hope to be Somebodies" giving it some cannon backing.
Others: An alternative of the above. Taken from Roxas telling Sora that he "make(s) a good other."
Oxycore: A hardcore oxygenarian run (where the player has no access to previously-earned gear and cannot eat or drink anything but gains some special rewards at the end), turned into a portmanteau for brevity.
Challenge paths are often tagged "-core" when stacked with hardcore restrictions — zombiecore, bearcore, beecore, and so forth.
Old Hero Team, Team Japan, Team Esaka - Kyo, Benimaru, and Daimon, with the last one being due to their theme music (which is usually entitled "Esaka" or a variation thereof).
The Pretzel - the motion for Geese Howard's Raging Storm attack: down-back, half-circle back, down-forward. So named because the thumb traces a pretzel shape on the directional pad while inputting the move.
The Almighty Stance - Robert Garcia's idle animation from Neo Geo Battle Coliseum and The King of Fighters XI, where he dances back and forth constantly. The name comes from the GameFAQs fighting games boards, where, during a discussion about character stances, a user declared Robert's grooving to be "almighty."
Cheesenitz - Goenitz.
Goenadz - Goenitz.
In some circles, all of ShenWoo's moves have nicknames, most of them consisting of "SHEN WOO <move>". Yes, uppercase is mandatory.
Wolfgang Krauser has a variation of this as well (his SDM is a throw where he, you guessed it, SPINS YOU RIGHT ROUND BABY RIGHT ROUND), aptly named "Krauserspin."
And now with 2002: Unlimited Match, Goenitz now has his own take on the fad, with his MAX2/HSDM summoning a tornado which SPINS YOU RIGHT ROUND BABY RIGHT ROUND LIKE A RECORD BABY RIGHT ROUND ROUND ROUND. We christen it the Goenitzspin.
Fathena for Athena's appearance in The King of Fighters XII, thanks in part to her Moeness and chubby legs. It's rapidly gaining speed.
The Amazing Flying Jhun: Yet anotherGood Bad Bug (the games are brimming with them). In 2003, one Jhun Hoon's aerial moves involved stomping on your head. If you performed a roll quickly after successfully executing this technique, Jhun would be left hovering in the air. In addition, his pushback would no longer be functional, allowing him to smash anyone open with the purest of ease. You can see the ensuing onslaught here and here.
Bandana Dee - A Waddle Dee wearing a blue bandana who originally appeared in the Megaton Punch minigame in Kirby Super Star. He was given a larger role in the Updated Re-release as a character in the Revenge of the King game, and is set to become a playable character in Kirby's Return to Dream Land, though the game still refers to him as simply 'Waddle Dee'.
Sailor Dee - Similarly, a Waddle Dee with a sailor hat that appears in the Revenge of Meta Knight game from Super Star.
Sugar Rush - Kirby's Invincibility mode after he eats a Super Lolipop.
Meta Knight - MK, Meta, and occasionally Sir Meta Knight (although that's canon in the anime).
Triple D (possibly originating from Escargoon in Kirby of the Stars), 3D, or DDD - King Dedede. Occasionally, D^3 or D3 crops up.
Bratsila/Bitchila - Bastila Shan; generally used by players who dislike her constant 'The Jedi Council is never wrong! You're falling to the Dark Side and will go to hell!" rants.
Captain Paranoid (self explanatory)/Fashion Disaster/Flyboy - Carth Onasi. Three words - The Orange Jacket. (shudder..)
Big Z - Zaalbar's in-game nickname.
Mish - Mission Vao
Candalore/Manderous - Canderous Ordo, following his promotion to leader of the Mandalorians in Knights Of The Old Republic II The Sith Lords. His army of Fangirls refer to him as 'Candy' or 'Candy-man" (usually this is very tongue-in-cheek).
Bald Old Coot - Jolee Bindo
T3, Tin Can, Mobile Trashcan - T3-M4
Tall,Pale and Jawless/Jawless Wonder - Darth Malak. Following the reveal of his full name in the KotOR comics (Alek Squinquargesimus), he gained the nicknames Darth Squinty and Darth Squigglypants.
Bigna - Midna's true form, also from Twilight Princess
Link himself. Every now and again, a new Link will come along and fans will struggle to give him a title along the lines of "Hero of ___." Never mind that only three Links throughout the series have ever had titles. Ocarina of Time Link, Wind Waker Link, and A Link to the Past Link.
And the Fan Nickname for Link from Twilight Princess is "the Hero of Twilight". (It really does suit him...)
Oftentimes, the titles - canon or no - are shortened to a single word, making Skyward Sword Link "Sky", Ocarina of Time Link "Time", The Wind Waker Link "Wind", and Twilight Princess Link "Twilight". Less commonly, A Link To The Past Link is called "Light."
On GameFAQs, after the picture of Link for the new "Zelda Wii" game was unveiled◊, Fi - the character appearing in front of Link - was (correctly) suspected to be the Master Sword. Then everyone tried to decide what to call her; they eventually decided on Steve. Alternatively, some decided to call her something along the lines of "Ms. Master Sword" or "Sword-Fairy".
Popeye the Smelly - William Nilmates. His appearance as a living corpse justifies the second part of this nickname; the first part is referring to one of his eyes falling out with an "OOOOOOPPPS" during your first meeting with him. Name coined by rpg.net user "Wields-Rulebook-Heavily" for his commentary on the game's proceedings.
Zombieman - The skinless character that Briggs meets near the end of the Darkmere chapter, who turns out to be the real mayor of Darkmere, as his outside body was hijacked by the Soul Taker that haunts the town. Also coined by Wields-Rulebook-Heavily.
Any criticism directed at Nexon, tends to be called Nexon Fail, mainly because of how many patches break more things than they fix.
"The Loli" - Mari, and the only female character in the game without breasts.
"The Emo" - Tarlach, since he always depressing things.
Goldbuyer - Anyone rich enough to afford nice clothing from player shops, doesn't mean they do, but just someone who buys expensive stuff. The sellers justification for high prices is usually "I'll just wait for a goldbuyer to buy it."
Gachapwned - Someone who bought Gachapon items from the cash shop and got lemons.
Sin - The Assassin class, because the extremely finicky swear filter originally wouldn't let you say "ass". Especially prevalent at that time since only the first two class tiers were available, so assassin was the highest class in its path.
BanditSin - A bandit that uses claw skills before advancement from thief (because the 1st job claw skill is so much better over 1st job dagger skill, and bandits get an attack skill upon advancement that renders the first dagger skill obsolete anyways). Also called "assbandits" by those who dislike this practice.
Hybrid Spearman - A Spearman who balances weapon use between spears and polearms.
"Starchild", "Godchild", "Godbrat", "Starbabby" (and more explicit nicknames) for The Catalyst at the end of the game.
The Catalyst is also one. It incorrectly conflates the designation the Protheons gave the location with the unnamed AI found inside it. The term isn't even stretchable since Catalyst literally describes what the Protheons were using that for, it wasn't just some random name they thought sounded neat.
Team Dextro - The Garrus-Tali squad. Refers to the fact that, besides being the only party members who can (potentially) be with you in all three games, they're also the only party members from dextro-amino acid-based species (contrast humans, who are levo-amino acid-based). This is a galaxy in which there are most definitely biochemical barriers.
"Grab" : almost all synchkills are called this, even ones, such as phantoms that don't involve actually grabbing the target. Probably because most synchkills do involve grabbing.
"magnet hands" or just "magnets": refers to a lag based issue where a banshee will drag a player a (sometimes considerable) distance before synch-killing them.
Brotarians for Batarians(from "Come at me bro"). The Batarian heavy melee atttack is also called the Falcon Punch due to it's slow speed and tremendous power.
May mulitplayer classes are referred to by a combination of their race and class, sometimes as an acronym. (GI for Geth Infiltrator, H Sol for human soldier. )
Kroguard for Krogan vanguard. Also called the "Krogod", due to being the tankist class in the game and the only vanguard commonly seen off-host(due to the vanguard bug). Dubbed by some as "The Murder Train".
Spamguard and Novaguard for the common human vanguard builds that involve using a combination of biotic charge and the nova invulnerability frames to fly around the map.
ShoulderMan - FlashMan.EXE from Mega Man Battle Network, who has an attack that involves removing one of the orbs in his shoulder. Name coined by comic author Reynard, who used it as a gag in his filler strips.
Pea-shooter - The initial weapon in Mega Man 1, rarely used after more powerful weapons are acquired from beating a boss, unless one is pursuing a Self-Imposed Challenge. A reference to the fact that the early games used the letter "P" (for "plasma cannon", its deceptively powerful-sounding name) to represent it on the weapon menu.
Mr. Decaf - Tom Dubius/Shinsuke Utagai from Mega Man Star Force, born from him initially being unnamed when he was unveiled in the anime, and the shadows under his eyes making him look like he needed some serious coffee.
The "1st" and "2nd Maverick Wars" to the Mega Man X and Zero series, respectively.
Green Biker Dude - The unnamed green biker who dies at the very beginning of X2, now a Memetic Badass.
The Eight Maverick Wars - The central conflicts in the eight Mega Man X games.
Boba Fett - Vile from the X series. His name is actually VAVA in Japanese, and no matter his incarnation (the original in X, Vile MK-2 in X3, or Vile V in X8), he actually looks like Boba. Even better; Vile V's primary coloration is green, making his similarities to Boba even more noticeable.
Nippleshirt and Ugly Pants - Names for outfits Snake wears in Metal Gear Solid 4. The Nippleshirt is the black skintight shirt he wears in the Briefings. The Ugly Pants are the green hospital pants Snake dons for his Fan DisserviceShirtless Scene.
Rape Truck - The truck Big Boss uses to kidnap soldiers with in Metal Gear Solid: Portable Ops.
Super Soldier - Allen O'Neal, Morden's bodyguard and Implacable Man extraordinaire.
Glen Achilles - The unused soldier prisoner in Metal Slug 5. Coined by Ragey of Metal Slug: Missing In Action. His anme apparently shows up as "[rank] Achilles" should you use hacking to rescue him and beat the level, though the first name was Ragey's invention.
Noob Bridge - A collapsing bridge in Super Metroid with spikes just above it. Crossing this bridge requires holding down the easily-overlooked run button while running across it, and many players ask how to get across this rather simple trap.
Noob Tube - The glass tube you have to break with a Power Bomb to get into Maridia. Another pons asinorum of the game. (c.f. Call Of Duty)
Iron Ted - The unnamed Ridley robot that serves as the real final boss of Zero Mission.
Also known as Mecha Ridley or Ridley Robot.
Charge Beam Beast, Beamst - The giant worm thing that drops Charge Beam. Another boss not found in the original Metroid or named in Zero Mission.
Bob - The one missile tank in Fusion that can't be skipped. (Technically, a method has been found, but it requires such precision that no one's pulled it off on a real GBA yet.)
Mysterious Black Dude - The at-the-time unnamed Anthony Higgs, who had never been seen in a prior Metroid game, yet whose only line in the Metroid: Other M trailer was, "Remember me?"
The Gauntlet - Upon entering the Phazon Mines in Prime, there is only a save room after approximately half the area, two minibosses, and dozens of Space Pirates. Also, the area of upper Crateria in Super packed with Yapping Maws, acid, an Energy Tank and two Missile Tanks is known likewise, since you have to repeat the whole thing if you flub the positioning for getting both Missile Tanks.
BSL (Blonde Scientist Lady) - Melissa Bergman as of her Other M appearance in the trailer, in the same vein as Anthony Higgs above.
El Pollo Loco - A giant chicken lizard thing that appeared in one of the trailers, for Other M.
Pseudo-Screw Attack/Ghetto Screw Attack - charging your beam and flipping into an enemy, just like the Screw Attack. It typically does more damage than the average beam, but it also does damage to you if you fail to kill the enemy you're ramming.
Then there's the Ninja Pirates that you fight two rooms away from Ridley in Super Metroid. so named because they don't shoot beams at you, but employ the use of shooting claws, martial arts, and jumping very high to fight you.
Mustard & Ketchup - Cyrax and Sektor, yellow and red cyborg Lin Kuei who are Palette Swaps of one another. These were, in fact, their names in pre-production before Cyrax and Sektor were decided on. In fact, one of Cyrax's Sambo combos in Deadly Alliance is named Mustard as an in-joke.
Flint Norris - Flint. Several members of the Mother series fandom compare him to Chuck Norris and he is sometimes called "The Chuck Norris of Nintendo".
Kuma or Kumi - Kumatora. Used as a shortened version of her name before the Fan Translation because her full name did not fit in the Japanese version using Romanji/the English Alphabet. Only 6 spaces were given to the player to name several of the main characters in the game.
Gang Rape - The Alien's Super Move that calls forth an entire army of Xenomorphs to gang-assault the opponent. So named because they're bunched very tightly on the opponent, and the lights strobe afterwards, giving that sort of impression.
Master Cheese - A Game Breaker version of Geese Howard named "Master Geese". Thus dubbed due to his ridiculously high attack strength and move roster that includes two instant-kill attacks.
It got to the point where someone made a fan-made sound file for him that replaced his vocals with comedy sounds. His intro? This fan-made SND changes it to... "I am The Cheese!"
Saavy, Saav, Saavi, Vedrey, Vedro - All nicknames for Saavedro, the antagonist from Myst III: Exile.
Whark - alternate spelling of "wahrk", one of the creatures from Riven; this was how one of the characters spelled it and some fans adopted that spelling.
Wahrk Gallows - The tall golden teepee structure on Jungle Island in Riven.
All of the islands in Riven have Fan Nicknames based on what structures they feature, and even those names differ amongst fans.
For example, the island you start on has been called Temple Island, Dome Island, and many others, due to the presence of both, while the final island has been called Catherine's Island, Prison Island, and other many things.
Mazerunner - An infamous puzzle from Myst.
Waffle Iron, Waffle Grid: The name given to another infamous puzzle in Riven that looks like a waffle grid.
Lava Chamber - That room in the age of Voltaic in Myst III: Exile that fills up with lava in order to solve one of the puzzles.
Sirrus' Guitar, Spider Chair - Yet another infamous puzzle from Myst IV: Revelation.
Ye Olde Grabbye Hande - The archaic-looking hand cursor as it appears in Myst, Riven, and Myst III: Exile - the last two games have redone versions of the hand cursor, and Uru Live has a differently designed cursor entirely.
The Stranger - The name given to the AFGNCAAP player character of the first four games.
Panic Link - What happens when your Uru Live character falls off a cliff, or towards another unsurvivable thing, such as lava - your avatar links back to his/her home age, Relto.