Incorporated into the mechanics of Ace Combat Zero: The Belkan War. Sparing noncombatants and wounded, fleeing aircraft earns you respect and means you don't fight the hardest aces (though the ones you do fight certainly aren't slouches), but earns you less money in the long run.
In Army of Two, Tyson Rios makes it a point to try to bring the conspirators within Security and Strategy Corporation to justice, even going to so far as to force Ernest Stockwell, CEO of SSC to turn himself in once they rescued him. His partner, Elliot Salem, who is much more pragmatic and selfish, repeatedly calls him on his honorable nature, pointing out that the two are mercenaries.
As Rucks puts it in Bastion "If you can't do something smart, do something right".
Averted in Bioshock. Though initially Jack is told that the only way to get large amounts of ADAM is to kill and harvest the Little Sisters, Doctor Tenenbaum makes it a point to give Jack gifts for choosing the harder path of rescuing the Little Sisters, by giving him both large amounts of ADAM and unique plasmids. Considering how much more great loot you get from saving them and how little the difference in ADAM between saving and harvesting all the Sisters is (over the course of the whole game), choosing to harvest the little sisters would be a case of Sadism Before Reason. (Or you might do it just to hear the ending where the good doctor calls you out for being a jerk.)
In Call of Juarez (especially Bound In Blood), characters will come along and challenge the protagonist to a gunfight, which he accepts. Never mind they have easily pulled a Malcolm Reynolds style move and simply shot them as soon as they showed up instead of doing the whole showdown thing. In the second game they are already outlaws anyway and no one else is around to tell the tale later.
Angeal in Crisis Core, honorable as he is he gave us a warning early on.
Angeal: But I never stole from that tree, because the wealthy man's son was my friend. Zack: If he was a friend, you should've just asked for some. Angeal: Honor can be quite a burden at times.
In the canonical ending of Jedi Knight, Kyle Katarn has Jerec disarmed and on his knees. Jerec tries to goad Kyle into killing him. Kyle responds by giving him his weapon back.
Lupa from Digital Devil Saga is a very strong believer in this philosophy. Tragically, it leads to his downfall because victims of the Atma Virus need to eat their opponents, or they become permanently berserk and have an insatiable bloodlust. Gale then takes up this philosophy after Lupa's death triggers his emotions.
Disgaea 2: If Adell makes you a promise, he will keep it.
Valvatorez takes this to the logical extreme. Want to know why he refuses to drink blood, at the cost of all of his power and prestige: because he promised someone that he wouldn't drink blood until he showed them true terror, and they died before it happened. Not considering death of the recipient a legitimate reason for breaking off a contract, he just went on not drinking blood for the next four hundred years.
More precisely, he learns that while his perfectly logical fighting style is effective, it doesn't allow him to exceed the limits he sets on himself. Only by ignoring reason and logic can he find the power to succeed despite overwhelming odds. He stubbornly refuses to believe that it changes his fighting style, though:
Onion Knight: Don't get me wrong, I still won't fight anyone I can't beat. So I guess I'll just have to beat you!
Alistair in Dragon Age: Origins has a lot of this going on. Being a Grey Warden, he considers it part of his duty.
Played for Laughs in Dragon Age: Inquisition. The Hand of Korth was supposed to attack the Tevinter Imperium, but somehow managed to get it into his head to attack you instead. After you kill him, his father (the chieftain of the tribe) declares his displeasure by smacking your holdings with goat's blood, as is the tribe's custom. Thing is, the chief is a lot smarter than his son, and knows this is probably going to get him killed. So he goes whole-hog and physically throws a goat at the castle. He's officially arrested for "laying siege to the walls with a goat." If you choose to "exile" him and his clan to Tevinter (which is what they wanted in the first place), it's one of the few decisions that every single one of your companions approves of.
EVE Online has this in the form of Amarr Empire battle doctrine, which completely forbids retreat or surrender. During their war with the Jove, the only battle they fought with them cost them most of their fleet because they couldn't retreat or give up.
In Fallout 3, with the Broken Steel DLC installed, while the player can send a radiation-immune companion character to activate the purifier rather than sacrificing themselves or Sarah Lyons, the game still considers this a cowardly choice rather than Negating Your Own Sacrifice.
Alluded to in Final Fantasy X. According to Auron, Jecht would often try and talk his companions into helping someone out because it was 'the right thing to do.' If he used that phrase, both Auron and Braska knew it would get them into a whole heap of trouble.
Gerik and his mercenaries from Fire Emblem: The Sacred Stones. When they and their employer Prince Innes are vastly outnumbered by an enemy army, Innes tries to convince them to surrender and save themselves since the other guys are only after him. Even after he fires them they refuse to (thoughhe orders them to surrender after firing them).
Innes: Unbelievable... and you people call yourselves mercenaries? I thought you fought for money, not duty. Gerik: Yeah, that's one of the rules. Guess we're lousy mercenaries, eh?
The Elites in the Halo series definitely fall under this trope. It's noted that during the Human-Covenant War, even regular Elites would fight hand-to-hand and die rather than pick up fully-loaded human weapons at their feet. That said, it's been shown in post-Halo 3 media that the Elites are starting to become a lot more pragmatic after the fall of the original Covenant; even anti-human Elites are ever more willing use human weapons if the situation calls for it (they seem to favor nukes).
Additionally, the Elites' taboo against shedding blood outside of battle means that many of them would rather die than see a doctor. Halo 5: Guardians shows that even the Arbiter still has some trouble getting his subordinates in the Swords of Sanghelios to seek medical attention, though it seems he's starting to make headway.
In the first Kingdom Hearts, Donald Duck briefly follows Riku in his evil phase due to a literal interpretation of King Mickey's orders. He later realizes this is stupid and returns to Sora's side.
In the Kirby series, Meta Knight will give you a sword in the favor of a fair fight, even when the fate of the universe is on the line. In one game, the two of you are on a damaged airship that is currently falling towards the ocean - and he'll wait a full thirty seconds for you to pick up the sword before deciding to attack you anyways. In another, the fact that his evil doppelganger doesn't throw you a sword is the first clue that it's not really him.
This is used for Idiot Hero Wain's Establishing Character Moment in Lufia: The Legend Returns. When a bolt of lightning sets a house on fire and a little girl is trapped inside, Wain rushes in without hesitation, pulls the girl out, then collapses from his injuries. Seena heals him, then asks what he would have done if she wasn't able to heal him...to which he replies that she could heal him, so it wasn't a problem anyway.
Averted in Mass Effect 2, where Samara, a Warrior Monk swears an Oath to Shepard so she will follow his/her orders, no matter how dishonorable they would be normally considered by her Code. However, she does inform them that if he/she does anything particularly dishonorable in the eyes of the Code, Samara will kill them when she is released from the oath of subsumation.
Either played straight or subverted depending on the player's whims in Mass Effect 3, where Samara attempts to kill herself as her Code requires her to kill her only surviving daughter. However, Shepard can intervene, allowing time for her daughter to provide an alternative.
Inverted with Javik in Mass Effect 3, he chastises Shepard for believing that that victory is possible with one's honor intact.
"Stand in the ashes of a trillion dead souls, and ask the ghosts if honor matters. The silence is your answer."
Zig-zagged with curing the genophage. If Wrex is in charge, especially if Eve is still alive, the honourable path - playing fair with an old friend - is also the reasonable one, since they can keep the krogan pointed at the enemy and direct them toward a brighter future, while backstabbing them for salarian support will end in Wrex dead, Mordin dead, and Clan Urdnot sitting the war out. If Wreav is in charge, especially if Eve is dead, curing the genophage - while still the noble thing to do - will ultimately end in either a massive krogan civil war, or a new Krogan Rebellions, and as a result the dishonourable option of backstabbing them becomes the most viable.
Enforced with Medieval II: Total War's Karma Meter. Characters can earn Chivalry points from doing things like sparing prisoners and lowering taxes, or Dread by executing POWs and exploiting peasants, that's straightforward enough. But on the battlefield you're abiding by medieval codes of chivalry, so "good" strategies are limited to frontal assaults against an equally matched opponent. If you use flanking actions, shoot down foes with archers, charge units in the rear, or use spies to gather intelligence - you know, tactics - characters will quickly pick up "Cruel and Cunning" and other Dreaded traits.
While several characters show signs of this, nowhere is it more apparent then in Colonel. By stubbornly refusing to allow his forces to be questioned by the Hunters due to his pride, he is hugely responsible for the Fourth Maverick War, which leaves himself, his sister and the rest of Repliforce dead. In fact, he is one of the few villains from that game who is completely unsympathetic.
Inverted in the Metal Gear series. Being a Stealth-Based Game, Snake isn't averse to using every dirty, underhanded tactic in the book to incapacitate/kill/sneak past his enemies, and Mission Control encourages the player to employ these tactics at every possible occasion, while the villains always announce their presence and proceed to give Snake a (relatively) fair fight instead of just killing him.
Metal Gear Solid 3: Snake Eater: The Boss inverts and plays this trope straight. Her Gambit Roulette ensured that she'd be dishonored and declared "the biggest traitor of this century," her personal honor keeps her from killing, and sometimes even passively helping Snake in his mission.
The End is a more pure embodiment, as he wanted "one last" honorable sniper battle. even if he gets the drop on you, he only ever knocks Snake out and drags him to an unlocked cell at a previous base instead of killing Snake. In turn, Snake is sad to disappoint The End if the player lets him die of old age, which causes the Major to chew him out over the radio for trying to be dramatic.
However, this trope is downplayed when you think about it. If you pay attention, he's actually staring at you while he's bowing, which is considered extremely disrespectful in Japan. He's not so much being honorable as he is being ironic.
In Quest for Glory 2, a fighter faces The Dragon in a climactic swordfight, and quickly disarms him. If he chooses to kill his unarmed foe, instead of letting him have his sword back, the game treats it as a dishonorable act... even though The End of the World as We Know It is due to happen in a few minutes, if the hero doesn't get a move on. The VGA fan remake is even more extreme in this regard; giving the sword back leads to a truly Nintendo Hard fight. Apparently, The Dragon waits until after you show him mercy to bust out the really nasty moves.
In Samurai Warriors, Naoe Kanetsugu embodies this trope to a tee, Azai Nagamasa less so (who splits this with his love of Oichi). Interestingly, the Jerk Ass Ishida Mitsunari actually adopts this trope by his decisive battle at Sekigahara by refusing an officer's suggestion of a sneak attack on the enemy, and revealing in his ending that his friends' honor tropes actually rubbed off on him.
A game mechanic in Sengoku. Honor is gained by such things as donating money to the Emperor and granting land to vassals, and lost by hatching plots and declaring wars. If a character loses too much, they commit seppuku.
Kasumi from Shakkin Shimai takes this to an extreme, refusing help from Okura even if it means she'll be sold into prostitution to pay off her family's debt.
Red from Solatorobo usually acts before he thinks, and, being a generally nice guy, he's usually acing heroically (or stupidly, but sometimes Good Is Dumb). He justification for rushing headlong into a mission that seems hopelessly outmatched is just "I Gave My Word."
Possible in the Star Ruler mod Galactic Armory. One Trait you can take is "Code of Honor", which prevents from using a variety of subsystems. No WMDs, fair enough, but when the thing prevents you from using sensible things like Armor-Piercing Attack it goes straight into this.
Luke, the protagonist of Tales of the Abyss, starts off as being extremely self-centered and arrogant, but later he becomes near-suicidally selfless in an attempt to make up for his previous behavior, and holds true to the strength and ideals of humanity, opposing the fatalist views of the game's antagonists.
The Half-Zatoichi in Team Fortress 2 is a katana wielded by the Demoman and the Soldier. It is Honorbound, meaning that once you draw it, sheathing it without drawing blood will hurt you, but you regain a large amount of health when you kill with it.
In the Warcraft Expanded Universe book Of Blood and Honor, the human paladin Tirion Fordring is an extremely honourable guy, saving an elderly man from a race which pretty much all of humanity was still recovering from having being nearly crushed by at the time. Doing so saw him exiled for treachery and his wife refusing to take herself and their son into the ruin he made for himself. His magical powers were supposed to have been taken from him, though due to nature of his use of them, it is assumed that they were granted by moral righteousness — which has since been debated and argued about in true nature, due to World of Warcraft.
In Warriors Orochi, Pang De's version of this trope is so cliche that he's called out on this more than once — hilariously, when one asks him what his "way of the warrior" even means, Pang De's explanation is basically repeating the concept. It's especially off, and call-out-on-worthy, since he's on Orochi's side through Wei, particularly Cao Pi's aligning with Orochi. However, in the Battle of Shizugatake (Shu story) if the player manages to save enough Hojo officers and prevent defections he will recognize the conflict and agree to leave Wei/Orochi.
In a rare villainous example of this trope, in Weaponlord, it has been prophecied that on the night that the moon bleeds, the Big Bad Zarak will be killed by the Weaponlord, whose identity is unknown except for the clue that he/she was born under the Warrior's Moon. Zarak's lieutenants advise him to pull a Herod and simply slaughter all the infants born under that moon, but Zarak instead decides to wait until the Weaponlord is grown up, and then face his prophecied killer fair-and-square in single combat to see if the prophecy will really work. This gets Zarak killed if you play anyone but him, and if you play Zarak himself, it is revealed that Zarak himself was born under a Warrior's Moon, and since he killed the previousBig Bad, Zarak himself becomes the Weaponlord.
Ronin leader Kazuo Akuji from Saints Row 2 suffers a terminal case of this. His casual disrespect of a gaijin Ultor Executive whom he deems as beneath him backfires when that guy —Bigger Bad Dane Vogel— immediately gives crucial intel to the Saints in retaliation, and his insistence on an honorable katana duel against The Boss goes awry when it turns out The Boss is a Combat Pragmatist who has no problem bringing a gun to a swordfight.
The White Knights of RuneScape apparently value the honour of a straight-up battle that would leave many of their number dead over the reasonable approach of sniping the enemy leader from above and behind, almost expelling the member of their order that took the latter approach to killing a dark magic-wielding enemy warlord.
Pointedly averted by the Temple Knights of Saradomin, an order of holy paladins in the service of a god of honor and nobility, who nonetheless immediately recruited the aforementioned shooter on the basis that he did get the job done.
The Arceans in Galactic Civilizations are all about honor, even at their own expense. This why, despite being generally nice enough guys to those who aren't their enemies, they are considered morally Neutral: honor is more important to them than any morality. A savvy player can exploit this to get the Arcean AI to do some very stupid things if they set things up properly.
In the backstory they react to Federation condemnation of their unilateral invasion of the Gorn Hegemony by breaking off diplomatic relations and beginning attacks on Federation colonies. Just like they did before the Dominion War.
In the mission "Diplomatic Orders", a Klingon cruiser commander gets information that a Federation diplomat is really an Undine. Does he submit his findings to the Federation? No! He leads a deep-strike into Federation territory to kill the ambassador himself, and instead of coming out firing, he sacrifices the element of surprise to high-handedly demand that the Federation PC hand over the ambassador. The Fed PC reacts surprisingly well to this: instead of just blasting the idiot out of space on sight (remember, the Feds and Klinks have now 'been at war for four years and the Klingon is asking a Starfleet officer on an Escort Mission to hand over his escortee to an enemy combatant), he asks to see the Klingon's evidence, and the Klingon instead takes umbrage and attacks, and because he's up against a Plot ArmoredPlayer Character he dies completely pointlessly and Starfleet makes the kill against the Undine.
Then there's "House Pegh", a.k.a. "House Pratfall"invoked. Emperor Kahless breaks away from a covert infiltration mission that is going surprisingly well because he sees an Iconian on a security camera and wants to challenge it to honorable combat. T'Ket at first ignores the idiot, then basically toys with Kahless for a while until B'Eler technobabbles away T'Ket's Nigh-Invulnerability. Instead of pressing his unearned advantage home, Kahless cuts off T'Ket's arm then starts monologuing about honor, giving T'Ket time to recover and vape Kahless. And then the "mighty Klingon warriors" of House Pegh, supposedly the Empire's covert ops arm, panic and run for their lives.
In the storyline of Mortal Kombat X Kotal Kahn, The Emperor of all Outworld, permits a foreign emissary of no great importance to challenge him in Trial by Combat for the life of a petty thief. His decision to personally participate himself instead of using a champion is questionable, although it may have been a calculated risk given that he's an incredibly deadly warrior. Less forgivable is that upon losing, he insists that the winner execute him as per ancient tradition, even though he's in the midst of a Succession Crisis and his death would give the throne to his hated, psychotic rival. He only survives because his opponent needs him on the throne and demands his service instead.
Alphadia Genesis: Walter, a knight from a neighboring kingdom who lost to The Hero, Fray, in a battle tournament, demands a rematch when they meet up again a year later and wants it now! Never mind that they meet up in a crowded tavern and drawing his sword in the midst of civilians while on an official mission for his king would have tarnished his honor far more than a fair loss.
A mission Grand Theft Auto: San Andreas has you sneaking aboard a large ship to free some Vietnamese hostages and then taking out the ringleader of the kidnappers. The player prior to the infiltration loses all of their weapons in a helicopter crash and when they confront the ringleader, he gives the player a sword so that the two of them can have an honorable fight to the death. However, nothing stops the player from swimming ashore and running to the nearest gun store to restock on weapons and going back to the mission area to blast the boss full of holes.
The Yehat in Star Control. In the second game you'll find they, formerly members of the Alliance of Free Stars as humans were, became Battle Thralls as their Queen prefered to surrender to the Ur-Quan rather than being the first ruler in the dinasty's two thousand years to lose a battle. Their oath of loyalty to her means that, as much as they dislike it they'll attack you at least until you bring them an Shofixti, what will cause a civil war between those loyal to the Queen and those who think she acted dishonourably.