Tournament gaming is quite prone to this. If you're holding back from using tactics that are legal yet you consider dirty, you're probably gonna get called a scrub and toasted by someone who will use them without a second thought.
Spawn camping in online shooters is based on this. Due to the reluctance of many servers to kick or ban a player for their first offense of breaking server rules, players may camp until the server gives them a warning. Even if the server specifically forbids it, the player can always feign ignorance and claim not to have known or can camp again but just a little bit further away from where they were before.
Any weapon in a PvP FPS game that has insane power, such as shotguns or grenade launchers. People who get blasted by such weapons tend to call the players who use them as cheaters or relying on a crutch to win, but unless the developers place a nerf on said weapons, complainers get told that they can use the "cheap" weapons as well in order to win.
Ryuji Yamazaki from Fatal Fury stomps people when they are on the ground and kicks dirt in their faces.
That's not even going into his Drill super, which revolves around brutalizing the opponent as much as possible while they can't fight back. In one variant, he pulls out his knife and stabs them several dozen times.
Something similar goes for, well, everyone in BlazBlue. All characters can use a crouching medium/kick attack on downed opponents to lift them off the ground and set them up for the next painful combo. That said, some characters have moves that are meant to be used on knocked down opponents.
A big part of Altair's fighting style in Assassin's Creed I is his willingness to be a brutal combatant. Included in his many nasty killing animations is punching a mook in the face to spin him around and then stabbing him in the lower back, through the hip, and out his crotch. Another involves breaking an opponent's leg by kicking out a knee, and another has him kick them in the crotch, and as they drop to their knees, stabbing them in the top of their head with his short blade.
Let's not forget his gruesome hidden blade counterattacks, which are so underhanded many players don't even realize they exist.
Unfortunately for him, by Brotherhood the polearm-wielding Seeker guards (and possibly other guards) will sometimes throw sand at Ezio's eyes or at your allies, while any guard is capable of grabbing Ezio — leaving him unable to block or counter any enemy attack unless he escapes first — and armored Regular guards will sometimes mount horses so as to charge and swing at Ezio, the only melee attack in the game that Ezio can not Counter with the Hidden Blade. Papal Guards will sometimes use a pistol, which like other projectile attacks can not be blocked or countered.
Although the guards get pragmatic-er, Ezio still wins the fighting dirty award for calling in henchmen to shank people.
One of the first tasks Haytham is required to do upon his arrival in the Colonies is to buy a sword and a pistol. This combination proves highly lethal, as Haytham (and by extension Connor) can opt to simply pull a pistol out of his coat and shoot an enemy. It's almost humorous to see the protagonist leaping around and violently slashing with swords and tomahawks, then calmly turn and shoot the last man standing.
Connor also isn't beyond fighting dirty, going for a nut shot in the fight against Haytham.
Desmond steps up to the plate, being perfectly willing to use a handgun after a foe mocks him for just using a blade. So he kills him and takes his gun, allowing the player a taste of just what an assassin of Desmond's caliber can do with a semi-auto pistol. And when that proves inefficient, he whips out the Apple of Eden, Old-Altair style.
It runs in the family. Haytham's father Edward doesn't shy away from brutal tactics either. Then again, he's a pirate, so why would he? Honorable pirates don't survive the Caribbean. One of the trailers show him killing a defeated enemy using the ship's wheel. Also, the final requirement to take over a fort is to kill its commander, who is unarmed and begging for mercy.
Kratos of God of War is pretty damned brutal, willing to stab Cyclops' in the eye, slashing their knees to open them up for attack, slam and throw enemies around and even rip enemies apart with his bare hands. The final battle of the second game has him pulling off an I Surrender, Suckers on Zeus, asking to be executed which he takes as an opportunity to give Zeus a No-Holds-Barred Beatdown. By the third game he's able to use enemies as battering rams.
Theseus breaks off direct combat to snipe Kratos and calls up minotaurs to aid him. Perseus reflects light with his shield into Kratos' eyes. Hercules calls up troops to aid him and throws chunks of the battlefield at Kratos.
Micaiah gets another one later in the game, where she shows she is quite willing to resort to dirty tactics like pouring oil on her enemies and lighting them on fire when the situation calls for it. Granted, this little ploy doesn't work so well when the Hawk King decides to retaliate with his own dirty strategy.
Virion, from Fire Emblem Awakening gets a spot of this in his supports with The Avatar. Playing a war strategy game, Virion constantly wins because he sacrifices his units, while the Tactician tries to keep them all alive (Similar to what the player does over the course of the game).
In Blazing Sword, this comes up in a support conversation; Legault mentions to Isadora that this is (apparently) how the Black Fang assassins fight, and even messes with her sword sometime during the conversation so she can't draw it.
The Amazon from Pro Wrestling is notorious for this. Some of the moves he uses to fight the other wrestlers include biting them, choking them and stabbing them with a fork.
In Super Smash Bros, many characters fight this way. But special mention goes to Wario. Some of his moves are: headbutts, shoulder strikes, clapping in the opponent´s body with his oversized hands, punch them in the groin, sit on them, gnaw on them like a shark eating his prey and fart on their faces.
In what might be a Take That against protagonists such as Leon from Resident Evil 4, Isaac from Dead Space wouldn't know "finesse" if it tried to claw his face off. Everything from frenzied curb stomping to strangulation while beating his victim around the head with a gun, the man can and WILL take any advantage offered in melee. Of course, when fighting a bunch of zombies, the idea of 'rules of combat' go out the window, but Isaac still qualifies by virtue of the sheer brutality he gets up to.
Isaac is less about brutality than panic-flailing. He is understandably freaked out by what's going on, and when attacked, he flails, panics, then gets a temporary advantage and freaks out, killing his opponent. Isaac is an engineer in a bad situation, he doesn't have any techniques or experience in that would help him; in essence, he fights dirty because he has no reasonable alternative.
Isaac's animations for getting out of grapples usually consist of pushing the necromorph back, punching it in the face and yelling till it ends up on the ground and then stamping on its spine. One particularly brutal example involves him stomping on a crawling enemy, and using the leverage to rip off its stinger-tipped tail with his bare hands. A more humorous example features him punting necromorph babies.
Isaac's weapons, in the first and second game, are repurposed tools, which just happen to be more effective than conventional weapons. By the third game, humanity has apparently adopted highly modular weapons due to the Necromorph invasion, largely based on those exact same tools.
Wario and Waluigi are these. Even though they live in a world where most characters can perform flashy super attacks( even they can), they often resort to cheating and dirty tactics. Wether it is tossing bombs, brute force, blinding the oponent or set some monsters on their tracks, these two will stop at nothing to beat the competition.
Pokémon is filled with some seriously dirty attacks. One of the first attacks you encountered in Red/Blue was Sand Attack, which is kicking/blowing sand in the opponent's face to reduce their accuracy. The second game adds Mud Slap, which uses mud (and actually does damage, too), and Pursuit, which strikes a Pokemon as it's being switched out. In fact, the "Dark" type combines not only obviously Darkness Elemental attacks, but also a lot of "dirty trick" attacks which invariably involve underhanded tactics or maneuvers, like Fake Tears, Bite, Torment, and Faint Attack.
The dirtiest Dark-type attack of them all is Beat Up, which works by having all the other Pokémon in the party gang up on the opponent. It's not called the Aku ("evil") type in Japanese for nothing.
The two types of Pokemon who take double damage from Dark-type moves are Ghosts (who are ironically rather timid) and Psychics (whose minds are broken by the sheer malice). But Fighting-types are trained combatants, and don't fall for such crap.
Bug Types and Fairy types also have an advantage against Dark types, the former likely due to the fact that Dark Pokemon tricks are designed for Pokemon without the sensory advantages insects have, and Fairies likely because they represent the supernatural force of good or Protection from Evil in D&D terms.
As mentioned in the Pokémon page, Croagunk and Toxicroak are like this, and learn a lot of dark attacks. However, it's for survival, and some of those species are said to be laid back and perhaps good. That may come from being Fighting-type though, most of them are honourable.
Another contender for most unfair fighter is the Poison element. Their modus operandi is right there in the name.
Apparently, according to many of their moves, Poison-types don't really like fighting upfront. Instead attacking by spitting/throwing up (Acid Spray, Gastro Acid), spewing gases (Smog, Poison Powder, Poison Gas), or setting up traps (Toxic Spikes).
In terms of protagonists, Wes could definitely be considered this. He's an ex-criminal who, in the introduction, blows up his former team's base, steals their Snag Machine, and then steals their Shadow Pokemon away from them.
And on the villains' end, Ghetsis in Pokémon Black and White apparently waited while you battled N so he could mind-break and attack the winner while all their Pokemon were still weak. This, after you'd already spanner'd the rest of his masterful plot.
In Black 2 and White 2, he just orders Kyurem to freeze the player character directly, instead of giving them the chance to beat him in a Pokemon battle.
Out of all the Dark-type Elite Four members, Grimsley displays this trope best. While Johto/Kanto's Karen and Hoenn's Sidney seem to like how cool they are, Grimsley has a firm belief that everything is fair game in battle, especially considering he used to come from a wealthy family that became impoverished. He even encourages the player to indulge in the same practice. The quotes section of the trope page has a gem from him that sums up his philosophy on battle:
Grimsley: A beautiful loss is still a loss, while an ugly win is still a win.
The Punisher game has this as a feature. If the player runs into an enemy, there are many choices. Hold him hostage, interrogate him, knock him out, shoot him in the head or just outright drive a k-bar into his brain. One of the many twists is the Punisher distracts the enemy by handing over his own gun, then it's knife-face time.
Metal Gear Solid is based around this trope. Solid Snake, Big Boss and Raiden are all expected to use whatever equipment they can scavenge (since their missions are black operations) in as many ways as possible. Basic examples include holding an enemy hostage in a firefight, knocking them out with sleeping darts, and distracting them by leaving Playboy magazines lying around. More advanced examples include "cheating" against various bosses. Snake can kill Sniper Wolf in complete safety with remote controlled missiles. Raiden can neutralize the bullet dodging Vamp by placing claymore mines in his path. Big Boss can land a cheap shot against Colonel Volgin by wearing a mask modeled after his lover, or skip The End entirely by assassinating him in his wheelchair. Each game has dozens of examples of this kind of trickery, and you are expected to discover and use these tactics. This however does not stop Big Boss from claiming somewhat ironically:
I'm no assassin. Shooting a soldier with their guard down isn't my style.
If you have inhuman strength in most games, it means you will use some kind of sword or other weapon. Of course, if you don't think about using a massive Gatling gun meant to be used in combat planes, like Vulcan Raven in the first Metal Gear Solid.
Perfect World's Assassin class. They can turn invisible at will (Shadow Walk or Shadow Escape), teleport to you from longer than the range of a bow (Shadow Jump), do the same thing while stunning you for 3 seconds (Shadow Teleport), immobilize, seal, sleep, or stun you while doing probably illegal amounts of damage (Tackling Slash, Throatcut, Deep Sting, and Headhunt respectively - especially Headhunt), increase their already ridiculously high crit rate by a huge amount while doing damage (Power Dash), dodge 1/4 of all your skills (Focused Mind), and are not fun to fight in PK unless you're a really good barbarian. At least the fight is fast. Unless you're a really good Barbarian.
Sword of the Stars has the Tarka, whose concept of "honor in battle" involves walking away with as few casualties as possible while leaving their enemies dead. Consequently they can and will employ almost any dirty trick in the book for an advantage; their favourite techs in-game are mines and torpedoes, and the game's novel has a Tarka commander betraying her own allies during a fight so that the telepaths they're fighting will be unable to learn her real battleplan from them — a battleplan that involves basically gift-wrapping the main character and handing him over to them on a silver platter so she can sneak up and stab them in their backs while they're preoccupied with... "processing" him.
StarCraft II is a prime case. Throughout a match's early- to mid- game, players typically target their opponent's workers or key structures with hit-and-run tactics, trying to gain an upper hand.
While all three races have some ability to do this, the Terran seem largely geared specifically for it, as is fitting for the Crap Sack World they live in. They have several units designed specifically for early game harassment and are easily able to deploy large armies in fast flying dropships, all of which can do immeasurable damage and retreat before you've had a chance to fight back.
In games that are played competitively or offer environment for competitive play, playing dirty and using mechanics that are considered overpowered by a large number of players is usually the norm. The game usually has a way of dealing with it or they are just things harder to counter than to employ, so they are 'overpowered' in lower levels of skill.
The Elites in Halo come off as a rather brutal example. They are proud warrior-race guys who have no problem with turning invisible in the middle of a fight. They may take pride in combat, but that doesn't mean they're stupid when it comes to that combat.
Humanity are huge on combat pragmatism, mostly because they absolutely have to. Since they're facing such a bad technology gap, they have to come up with devious and unusual strategies to make up for it. But even when they don't, they use particularly brutal methods. The human military kidnaps hundreds of children, replaces them with short lived clones, training those children to be soldiers, then subjecting them to drug enhancement therapies which may kill them or leave them seriously crippled. To make the ultimate soldier. And that was before they made contact with the Covenant.
After they meet the Covenant, they come up with a slightly different program. At least the SPARTAN-IIs were designed to survive any conditions and come out on top. The SPARTAN-IIIs were trained to be cheaper and disposable soldiers for key operations. Despite this, many claim that it was more humane than kidnapping children.
While most of the boxers of Punch-Out!! have rather unconventional movesets, to put it mildly there are characters who use Martial Arts alongside boxing (Dragon Chan) as well as weapons (Hoy Quarlow). AranRyan in the Wii version however is the biggest example, using elbow strikes, head butts, putting horseshoes inside his gloves and later on using a boxing glove whip against you that lets him get a free hit in upon knocking him out.
It's hard to get more pragmatic than Prototype's Alex Mercer. Anything that isn't nailed down or on fire can be thrown at enemies, any civilians unlucky enough to be within range of his wild flailing get torn to shreds, and he heals himself by eating anyone still standing. He is also a shapeshifter, and not even slightly above becoming a soldier and accusing another soldier of being him to get them shot, or taking the shape of a commanding officer and ordering "his" troops to bomb each other, or playing dead to escape when cornered.
This is taken further in Prototype2; rather fighting fairly, it's possible to stealth inject a mook, prompting them to explode tentacles all over that latch onto and pull everything and everyone nearby inwards, crushing anyone unlucky enough to be close.
In World of Warcraft Rogues are one of the dirtiest fighters in the game. They can become invisible in combat (Vanish), they have several abilities that incapacitate opponents, such as Blind, Kidney Shot, Backstab, Ambush, Cheap Shot, Garrote, and poisons on their weapons.
It doesn't help that players behind the class are fond of attacking you while you're low on health or already engaged in combat, further capitalising on their advantage.
In fairness, players of every class will do that.
Really, many classes fight dirty when their spells are taken literally. Priests can use psychic-magic based abilities to mentally torment enemies to death, not to mention the ability to infect enemies with a literal Devouring Plague.
Okay World of WarcraftPvP players, raise your hand if you've come across someone of the opposite faction battling with something, waited until their health was low, then attacked for the honor points. Rogues need not reply, assuming you haven't already stealthed and snuck up behind me.
Many attack for the lulz or factional pride, but it's much the same.
Players with the Engineering profession can take this to new heights, being able to use flamethrowers and rocket launchers in a high fantasy setting. This is taken to the fullest heights with the Big Daddy bomb, the highest ranked bomb in the profession to date, which does massively increased damage if the enemy is out of combat, meaning that a level 70ish character can creep near an enemy respawn point, let everyone respawn, then hit the whole area with up to 15,000 damage, which is enough to one-shot most characters at that level.
Dampierre from Soul Calibur: Broken Destiny loves to fight dirty. Along with his pair of hidden-below-the-forearm blades, he will also throw sucker punches during throws, and even fake injury right before springing up and attacking again.
In Spelunky, one of the protagonist's main abilities is the ability to pick up and throw anything. Priceless golden idols, enemy corpses, Distressed Damsels, you name it, he can throw it. Damsels can also be used for a host of things besides the reward you get for rescuing them, including the infamous"damsel bomb" trick. Other pragmatic tricks include getting a Ballistic Discount at a shop, and luring enemies into the vicious Death Traps meant for you.
Some of Batman's moves in Batman: Arkham Asylum easily qualify for this trope. One of his delicate ways of saying 'stay down' is to wrench someone's lower leg by ninety degrees to the sound of breaking bones. That's gotta hurt.
Aside from Batman's vow to never take a life, most of Arkham Asylum's combat is like this. In freeflow combat he routinely breaks bones, dislocates joints, turns enemy weapons against them and generally does whatever most expediently neutralizes the threat. When facing thugs with guns? Use stealth, environmental traps, misdirection and psychological warfare to whittle them down one by one without a shot being fired (if you're good).
The salarians in Mass Effect always start their wars with no warning, either hitting an enemy pre-emptively or assaulting their targets out of the blue. The Codex entry for their military doctrine even explicitly states that they view the concept of warning your enemy you're about to attack by declaring war is insane and stupid.
The same codex entry states explicitly that Salarians believe that a war should be won before it begins.
Hence part of their problem in 3 is their sheer lack of experience on how to deal with prolonged war with entrenched Reaper forces.
Shepard him/herself - a Renegade can sometimes punch/shoot potential problems through dialogue options. The Renegade Action Commands in the second game more or less consist of attacking or threatening suddenly. And punching that reporter.
And now, in the sequel, there are optional Quick Time interrupts in which Shepard can cut people off by shooting them, punching them in the face, throwing them out skyscraper windows, etc. This has the bonus of making certain scenes a lot shorter, not to mention easier. In one case, doing this will take out a half dozen opponents, leaving you to face only one. And all without taking damage, thanks to the magic of cutscenes.
And due to way the morality system works in the series, there's barely anything stopping a Paragon Shepard from being a full Combat Pragmatist themselves. When the situation presents itself, s/he can take a Renegade option to even the odds (or greatly tip them) in a firefight with no effect on their Paragon ranking.
Infiltrators in particular have no moral objections to becoming completely invisible, shooting people clean through walls with heavy sniper rifles, hacking turrets to go after the engineers deploying them, and even - with the correct DLC for 3 - mind-controlling enemies into beating the snot out of each other.
Humans in Mass Effect have an equally pragmatic doctrine - they go after enemy supply lines and the like, leaving their forces to "wither on the vine".
Humans are also said to be fond of Disproportionate Retribution. They don't have the manpower to guard each of their colonies, so they make sure that whoever attacks one is in for a world of hurt. Word travels around, so the human colonies are usually left alone...
Humanity's tactic of keeping fleets of warships in arms reach of their colonies is said to have caught the Turians off-guard during the First Contact War. They thought that the vessels in orbit around Shanxi represented the bulk of Human military strength, only to have a collective Oh Crap when they noticed an entire Fleet of angry Human Warships pouring through the Relay and establishing enough weapon-locks to blast them out of the stars.
Inverted with the Geth (minus the Heretics), at least when fighting other geth. Due to their nature they tell each other everything, even plans for attack. Legion finding out that the Heretics have been spying on the other geth horrifies them.
The Cerberus Daily News goes into detail on just how vicious the turians are in combat, particularly when dealing with a rebellious province in one of their colonies. Since every turian is a soldier, turian military doctrine does not distinguish between civilian and soldier, and in a turian vs. turian war, they bomb their own cities indiscriminately. A common practice in these types of engagements is to establish "safe camps" near a combat zone, where enemy adult turians who do not wish to fight can surrender and move to to remain out of combat. Any able-bodied enemy turian who isn't in the safe camp when combat commences is a legitimate target. This tendency was also shown when the humans were fighting the turians at Shanxi; the turians were not particularly concerned about civilian casualties and were consistently bombing human squads from orbit, destroying entire city blocks to kill individual fireteams.
And then there's their handling of Tuchanka.
Joker: You gotta love the turians. After they beat you down and sterilize you, they strap a big old bomb to your planet. Y'know, just in case you get uppity again some day.
Kai Leng in Mass Effect 3 is not above calling in a gunship to provide cover-fire while he recharges his shields or calling in reinforcements in boss battles.
This is basically the plan driving the plot of The Arrival DLC for Mass Effect 2. The Alliance plans on blowing up a mass relay, which would temporarily stop the Reapers. Mass relays are pretty much nearly impossible to destroy through conventional means, and an Alliance Fleet showing up in batarian space would spark a war. So the Alliance team covertly straps engines to a small planetoid to fire it at the relay Ironically, strapping rockets to a small moon to perform a Colony Drop was the same trick the Batarians used in the Bring Down the Sky DLC from the first game, which was narrowly averted by Shepard. Clearly humans learnt from the incident.
Miguel from Tekken is a pretty dirty fighter, even having one move that starts off with you laughing at the opponent unguarded and then just punching them in the face for a one-hit KO.
King is pretty pragmatic himself, with those crazy grapple combos, even grappling opponents while they're in mid-air.
Also, pretty much any character that isn't human or that has superhuman capabilities can be considered a combat pragmatist.
Yoshimitsu, for example, who comes to a fighting tournament in a suit of protective armor, the ability to teleport behind his enemies & regain health during a fight... oh yeah, and he uses a SWORD! In some versions of the game, it's practically a lightsaber!
Apparently stomping on enemies is a divine move, as is attacking enemies in the crotch as both are in his Roulette Wheel (which has moves such as God Charge and Divine Smash). The latter is useless against women and Camp Gays though.
End Credits: "Don't act like you don't like the Ball Buster!"
The MMO Dungeon Fighter Online epitomises this trope with the "Brawler" subclass. The Brawler throws sand in the opponents eyes, uses bladed fist weapons (though any fighter class can equip them, the Brawler specializes with them), poisons said weapons, throws nets at opponents, and more.
And that's relatively tame, considering that Gunners are willing to use flamethrowers and airstrikes in the same situations.
The bosses in Dawn of War II will always call reinforcements when you fight them. Particularly nasty is the Avatar of Khaine, which likes to call in lots of tanks.
Kind of justified considering that you can Deep Strike.
Wrestling skill in Dwarf Fortress, aside from the obvious locks, throws and chokeholds, lets you do such interesting things as gouging out eyes, twisting your weapon in the wound, and tearing off parts of the other guy's face. Sadly, the AI doesn't make very efficient use of it.
This being Dwarf Fortress, ways to set up elaborate and extremely brutal deathtraps for your fortress abound, and the instructions for any one of them can be found on the forums or wiki, often with diagrams. One of the easiest "traps" to develop is the "Dwarven Atom Smasher": Build a drawbridge over solid ground, trick enemies into walking beneath it, and lower the drawbridge onto your foe. The main drawback to this method is that the enemy's belongings are also crushed, so you don't get any loot for your dwarves, and extremely large or strong enemies won't be crushed. In order of increasing complexity from there are pitfalls, drowning traps, magma traps, "Goblin Grinders" forcing your enemies (or cats or other undesirables) to walk in circles endlessly across repeating spike traps, and the "Dwarven Checkerboard", which isolates demons and then covers them in magma and water to encase them in obsidian, possibly allowing you to ride out what was supposed to be a game-ender. Being terribly, terribly unfair to your foes is the way to survive in this game, as the game ain't playing fair either.
A rather humorous example in Adventure Mode: werebeasts are extremely difficult to defeat in beast form unless you have weapons of the right material, but since they're only monster one night per lunar cycle and you know where they are anyway you can just attack them while they're a naked peasant.
In Street Fighter IV, Balrog and Cody both qualify. Granted, the rules of the tournament are shaky at best, but in Cody's case it's probably safe to say pulling a knife or hitting people in the spine with a pipe are probably against it. In Balrog's case, one of his Ultra combos involves him stepping on the opponent's toes to hold them in place before he beats them about the face. It ends with a hilarious "Who, me?" shrug towards an unseen ref, who may exist only in his head.
As well as C. Viper, who hides various gadgets in her clothes.
Though he's very much the Cultured Badass and Balrog's Good Counterpart, Dudley isn't unwilling to use moves that would get an actual boxer disqualified, including all his throws. Unlike Balrog, though, it's indicated that Dudley only does this when he's street-fighting. It's possible that he does this to lure his opponents into a false sense of security.
In the MMO EVE Online, all the most successful players who fight other players will do anything to win, such as using ridiculously superior numbers to ensure a kill. Many will even engage in metagaming where they will infiltrate enemy alliances to find out where enemy players are, what ships why're flying and how they're fitted out, what tactics they use and how to counter them. Some will even infiltrate in order to pretend to be on the enemy's side, stabbing them in the back when a fight commences. All of these are considered acceptable tactics by not only the PvP playerbase, but also the game developers who actively encourage it. The common response from PvPers in EVE Online to anyone who complains about these unfair tactics is that a kill is still a kill, and there is no such thing as "Space-Bushido".
There's a rumour that some players physically went to a foe's house and made noise so that he couldn't sleep, which greatly reduced his combat effectiveness.
There is another rumor that during a war between two ingame alliances, members of one alliance were planning to cut the power to the house of the fleet leader of the other alliance during a battle.
Of course it seems like both of the above mentioned tactics were in fact criminal in nature, trespassing and vandalism, and could have gotten the players arrested.
Intelligence and resourcefulness are the most respected traits one can demonstrate in EVE Online combat. A player will gain far more recognition for using unconventional (often called "dirty" by newbies) tactics to achieve victory.
In Fallout 3 it might seem cool to use melee weapons against other melee attackers or even fight unarmed like a ninja with the right skills and perks, but often all this is relatively impractical when you will have a much easier time throwing a grenade into a room full of Mooks.
Also the VATS targetting system makes getting a kill painfully easy as it is a turn-based system that allows you to target body parts and score better critical hits. The only thing limiting it is the number of action points you have available, meaning you're forced to fight in the conventional fps style from time to time. And even THIS limitation can be overcome by a high level perk that instantly refills your action points upon just one successful kill in VATS, which essentially means almost infinite use since enemies that can't be killed in a single VATS barrage are practically nonexistant past the first few player levels.
Even more so in Fallout 1 and 2 where you could aim at the eyes or groin, with a freaking Gatling gun.
Ulysses of the Lonesome Road DLC will not only use Stealth Boys and Flash Bangs on the player should you choose to fight him, he'll also have the aid of a swarm of Eyebots and sic the Marked Men of the Divide on you.
This is how the Legion operate in New Vegas. Caesar favors total war tactics, which are generally incredibly brutal yet effective. According to a retired Ranger, the Legion are not above using children as suicide bombers and Vulpes Inculta in particular had no problem with dirty bombing Camp Searchlight. Legate Lanius however dislikes such tactics as he sees them as dishonorable.
In Grand Theft Auto: San Andreas, you, CJ, comes up against the head of the local Triad. In the final showdown, he tosses you a Katana and you do duke it out with him using Katana swords. Sounds fun right? But this is Grand Theft Auto. Most players will more than likely have a couple guns on them. Why bother fighting the guy when you can just pump him full of lead right?
Kingdom of Loathing gives you the option of playing as a Disco Bandit, who specialises in enemy-weakening attacks. These include a suckerpunch, an eye-poke, a face-stab, breaking your opponent's knees with a spinning kick, and pretending to run away then attacking while your opponent's guard is down.
In the second Fable game, you are sent to find the Hero of Skill and get them to join your group of Heroes. Reaver turns out to be...not as nice as the other Heroes on your team. His combat pragmatism becomes apparent when one finds out why his signature pistol is called the 'Dragonstomper .48', as discovered in the description of the pistol the 'Red Dragon'.
The description of the 'Red Dragon' is: This unique an exotic pistol once belonged to Wicker, the finest shot Albion had ever seen. Until Reaver appeared. Wicker visited Reaver and challenged him to an honourable shooting challenge to decide who had the greatest skill. Reaver's reply was to shoot him in the head.
In Diver Down Drek fights like this in the cutscenes. No action is too underhanded or dishonorable when his survival is at stake. In gameplay, not so much.
Team Fortress 2 - it's said that if you're not winning, you're clearly not fighting dirty enough.
Pretty much a staple of playing the Spy correctly; if you're not abusing the enemy's trust and tricking them for backstabs, you're doing it wrong.
Demomans could count as well, placing sticky bombs in front of the spawn entrance are a tactic used by the majority of players and bots as well.
Considering there are many counters to this (including airblasting and blowing them up before they blow you up), it is not as effective as before.
Engineers can be just as dirty. Tip: Never assume you've got him at your mercy, unless you like getting swiss cheesed by the sentry he lead you to.
Medics forced to kill someone themselves never fight fair, they abuse their Healing Factor, superior speed, and their favorite weapon, the Blutsaugr has Life Drain to boot, they basically shoot you, get out with half health, heal up, repeat, until you're dead.
Heavy may seem to be the simplest and most straightforward class. This is until you find one of the good ones doing things like sneaking behind the enemy team to mow down all of them before they realize the bullets are coming from the other way. Heavies with the Tomislav in particular are fond of waiting just behind a corner to mow down anyone who comes in.
In The Godfather 2, Dominic can use vicious moves such as neck punches and arm breaks.
Bayonetta simultaneously subverts and plays this trope straight. Since the game puts a lot of value in stringing together combos and generally killing your opponents quickly, there are a lot of ways to make her fight very pragmatically from using her enemy's own weapon against them to shooting them while they are speaking. The subversion comes from the fact that while she plays unfairly in nearly all of her fights, she has a habit of being incredibly over the top to the point where whatever benefit she gained from dirty fighting is negated by her showy nature. Thankfully, her explosive power makes her make the best out of this situation without much of a problem.
Shadow from Sonic the Hedgehog is this. Despite having Super Strength, Super Speed , and a slewof otherpowers, he is quite able and willing to wield any sort of weapon, be it guns, explosives, vehicles or improvise with debris. He doesn't naturally hold back against opponents, and also has no qualms against using lethal force against weaker or defeated foes in gameplay and several of the games. This goes against the Does Not Like Guns (Sonic) or Bare-Fisted Monk (Knuckles) mentality of other characters.
Rangers from Guild Wars. They have Throw Dirt which can blind enemies for a period, making melee attacks useless, can target enemies' legs and cripple them and slow movement, an assortment of landmine-like traps, and when the going gets tough, they even have a skill called Escape that lets them run faster while having a high chance to block any attack aimed their way. Fighting dirty indeed.
Assassins also fit this trope. Aside from being the only class in the game that can teleport, their attacks also feature liberal use of poison, knockdowns, crippling, and disabling enemies in various ways. They also have their Dark Escape skill, which halves their damage intake and gives them a speed boost, making them very tough to kill when fleeing.
And let's not forget the Assassin's infamous Shadow Form skill, which in PvP, makes them IMMUNE TO ALL ATTACKS AND SPELLS, while the Assassin is free to cause whatever damage he sees fit. There's a reason Assassins are feared in PvP.
Mesmers are practically the personification of this trope. Among their bag of nasty tricks, they can steal spells off your skill bar, cancel nearly any skill you begin casting, inflict massive armor-ignoring damage on you for doing anything, including nothing at all, completely drain your magic meter, and even send your skills into cooldown mode for absurdly long periods of time. Mesmers are also feared in PvP for this very reason.
Etiquette hasn't gotten much better in the sequel. Engineers have a "tool belt" which gives extra attacks depending on which kit or skill they have equipped, including firing a bullet (or ROCKET) from their belt buckle even when knocked down and stunned; Thieves fit the standard "stab everything in the back with a poisoned weapon" niche with at least one ability that makes EVERYONE AROUND THEM stealth for a few seconds; and one particularly viable PvE build for Rangers boils down to "poison, blind, cripple and generally render your enemy helpless while your pet walks up and casually eats their face."
Rogues in Dragon Age are built around this, with a focus on backstabbing (especially the Assassin specialty), and such abilities as "Dirty Fighting," which appears to throw sand in an enemy's eyes to stun, and "Below the Belt," which is described as a "swift and unsportsmanlike kick".
The game itself gives you a few opportunities to do this, even if your character is not a rogue. Your Warden can for example drug/poison his/her enemies before the fight.
Grey Wardens in general are supposed to have this attitude. When you're the only thing standing between the world and a Blight, who cares if you have to resort to blackmail and Blood Magic?
Similarly, the Imperial Agent specializes in assassination, with poison, sniping and backstabbing as their specialties. Considering that both classes are Badass Normals going up against Jedi/Sith, they're going to need some tricks to even the odds a bit.
Also, if Kaliyo Djannis is around when the Imperial Agent confronts Darth Jadus in the finale of the first act, she'll eventually decide to shoot him while he's gloating. Unfortunately for her, Jadus simply teleports away and responds with a Force Choke.
Several characters in the Star Wars: The Force Unleashed, especially Starkiller, who throws in punches, kicks, and grapples during lightsaber duels and can turn nearly anything into an Improvised Weapon with the Force. Special mention is his incarnation in the non-canon Ultimate Sith Edition, where he throws Luke Skywalker in the path of a snow speeder!
Stryker, Sektor and Cyrax also count. Stryker, being a police officer, has a gun, a nightstick, a stun gun, a flashlight and a grenade (because... explosions are cool). Sektor and Cyrax, being robots, have a variety of gadgets, such as explosives (missiles and bombs, respectively), flamethrowers (Sektor), energy nets (Cyrax) and a chest saw (Cyrax).
Fallen Earth has a whole skill tree devoted to this tactic known as "Dirty Tricks". The skills include moves like "Dirty Steel", "Kneecap" and "Sabotage". The icon for the Dirty Tricks skill set is a man getting kicked in the junk.
You can be one in Dark Souls. As a Black Phantom, you can use environmental traps, back stabs, and cliff ledges to ruin your target's day.
Any player character in The Elder Scrolls who has a high sneak skill probably fights in the most unfair way possible. Sneak up behind a foe and stab them with a dagger or fire a poisoned arrow at their face before they know you're there are common tactics for a pragmatic character. Pragmatism is the name of the game with a thief-type character, especially, because they're basically Glass Cannons.
In Lords of the Realm II, you can attempt to fight honorably and use your armies to battle other armies or castles. Or you can go into the other lord's lands, destroy their crops and pillage their villages, and then sit back and watch as the peasants get upset and throw an uprising against the lord. It doesn't matter if there's a royal castle, that land becomes forfeit.
Only shooting people is so passe in Syndicate (2012). Blow up their weapons in their hands! Make them kill themselves or turn on their allies! Hack the environment to use it against them, like making a fuel line leak and ignite, or turning a sentry gun! See and shoot through or around cover!
In the second Knights of the Old Republic, the Exile is forbidden from using the Force during sparring matches with the Mandalorians. However, since Kreia is in Force-bonded with the Exile, if she should happen to buff herself with Force abilities before the match...
The sparring matches against the Handmaidens show why the Mandalorians included this rule. You can win every round by force-pushing your opponent out of the training circle.
In the first game, one Dark Side solution on Korriban is to pull an epic multiple-cross in which you poison both the people trying to manipulate you into helping them kill the other, then slaughter them both.
Call of Juarez: Gunslinger allows you to draw your revolver in a duel earlier than your opponent, although this is regarded as a Dishonorable act and will give the player a much smaller reward.
To BioShock Infinite protagonist Booker DeWitt, fighting unfair isn't just good tactics: it's the key to survival. From the opening ingame fight, (where he distracts the officers holding him hostage with a baseball before shoving one officer's face into the other's sawblades), his takedown methods with weapons (shootings, stabbings, decapitations), to his brutal Vigor-based executions (burning enemies alive, summoning man-eating crows, suspending enemies in the air where they can't defend themselves), he makes good on his advice to his companion Elizabeth: "If you don't draw first, you don't get to draw at all."
Virtually every single fightscene in Heavy Rain devolves into a completely improvised mad dash to whatever object the characters can get a grip on and clubbing, beating, or stabbing it into their enemy, whether it's a samurai sword or a tv screen. Almost every fight has the players caught off guard, and every characters has some form of handicap or inexperience leading their fighting style to be completely panicked.
Sora in Kingdom Hearts is this; he's somewhat lacking in true swordsmanship, so he uses his Keyblade as a club. The second game, in particular, gives him numerous Action Commands that depict him disarming opponents and attacking from behind.
Also, Riku knows he can't beat Roxas in a straight fight, so he simply gets his Guardian to strangle him from behind.
Hitman protagonist 47 will use virtually any means necessary to eliminate his target - ideally before said target even knows he exists or is in the area. Why get into a gunfight when you can put on a disguise and ambush him? Or plant a car bomb? Or just snipe him from a safe distance?
The very first set of missions in the first game put this into a stark light: his target is a man in charge of a criminal empire, who never shows his face in public and is therefore unkillable by virtue of being untouchable. So 47 arranges for his empire to go to war with another empire, then drives it to increasingly violent ends, until the target is forced to show his face. 47 then (tries to) poison him.
Command & Conquer players never play fair by anything other than the in-game limitations. The usual response to someone trying to counter an all-tank army with infantry is simply to explain that tracks and wheels are the best anti infantry weapon in the game. And by explain, they mean show. The other guy better at Micro? Ignore micro and just focus on building a better economy while he's busy micromanaging his army and swamp him.
At one point in Long Live the Queen, Elodie may be challenged to a duel to the death. This is a dangerous situation if you lack skill with swords, since the challenger won't take no for an answer. Unless, that is, you've been training up magic, and just blow the guy up from a safe distance.
The protagonists in Spec Ops: The Line become increasingly pragmatic as the game progresses, using brutal takedowns and burying enemies under hundreds of kilos of sand.
There is a reason why the Condemned series has been called a bumfight simulator. 2x4s, pipes, axes, shovels and bricks can be used in both games.
Deconstructed with Virion in Fire Emblem Awakening, however it's applied to a chess setting. The avatar is a complete genius at strategy, yet is never able to beat Virion at a chess-like strategy game. When the Avatar suggests that Virion lead the army, Virion points out that this is the reason he wins. Virion always manages to outsmart the Avatar by using tactics that would work to win battles, whereas the Avatar becomes so fixated on trying to win without losing a single piece - just like all players of Fire Emblem.
Bristleback in Dota 2. People generally fight less effectively if they are covered in snot, see, so he'll gladly shoot enormous gobs of the stuff out of his nose at you to help his chances.