Text Adventures often rely on exact words, and if they're particularly sadistic, will give good and bad results depending on which word you use, even if said word is equally valid. Many of them will allow you to use multiple words for the same meaning but will not recognise some words, or they will recognise archaic words but not modern ones, if they are going for a certain feel.
In Sonic the Hedgehog (2006), Mephiles told Silver that the Iblis Trigger (Sonic) was going to destroy the world. He never said exactly how it was going to destroy the world...
In Sonic Colors, one of Eggman's public announcements touts that "no animals were harmed in the creation of this park." Which we can believe...because within the same announcement, Eggman then states that the animals were harmed after it was created.
Super Paper Mario had something similar. The Dark Prognosticus stated that the man in green, Luigi, would use the Chaos Heart's power to destroy the world. That turned out to be completely true. What it didn't state, however, was whether Luigi would do so willingly, or rather, whether he would do it if he wasn't brainwashed by Dimentio by planting a floro sprout in his brain beforehand.
Morrowind has a minor example of this. One quest has a reward of Boots of Blinding Speed. The boots do cause you to be incredibly speedy... and they also cause you to be blind, making them completely ineffective. Unless you happen to be a Breton, in which case the 50% natural spell effect immunity means you only get half-blinded (actually everything just gets somewhat darker). Strangely, you still benefit from the full boost to your movement speed... This is because magic resistance only applies to negative spell effects, for balancing reasons. It would be impossible to ever buff or heal yourself otherwise, after all. You can also enchant a helmet to give darksight. Useful in caves when you don't have a torch, even more useful for countering the boots' darkness.
Song of Hrormir tells the story of Hrormir, an honourable warrior who swears the following oath to Nocturnal: "Shadowy Hag, to thee I pledge, To only honor thy black Words, To turn my back on Truth, To aid thy Dark Kings' Ambition, To divide their Inheritance fairly, To love thee, To think thee beautiful." When he later betrays her, Nocturnal realises that the part of the oath "turn my back on truth" allows him to escape honoring the rest of his agreement. Annoyed and impressed by his cunning, she releases him from her service.
In Skyrim, during your initiation into the Dark Brotherhood you are required to choose one of three bound prisoners to kill. You are told by Astrid, the leader of the Brotherhood that "No one is leaving until someone dies". You can leave by killing a prisoner or Astrid herself.
In Odin Sphere, the demon lord Odin asks the shadow knight Oswald to slay the dragon Wagner in exchange for a castle, a magic spear and the hand of Odin's daughter Gwendolyn. After Oswald slays Wagner, Odin demands Oswald give him the magic ring found in the dragon's belly, but Oswald, already planning to give the ring to his new wife as a wedding gift, refuses and points out that Odin only asked him to kill the dragon. When Odin insists, Oswald threatens to kill him and demands his reward, forcing Odin to back down.
In one example he does this without being outright evil. Hammerhead's ending in TM2 has the two drivers wish to fly; Calypso says "Wish granted", and the pair immediately runs off the nearest cliff... while a dumbfounded Calypso looks on, plane tickets in hand.
In II, Mickey stops Sora and co. before they can go help everybody else fight off an army of Heartless in Hollow Bastion. He tells Sora to leave immediately to search for Riku and Kairi despite his protests, and then orders Donald and Goofy that they need to stick together with him no matter what. They both agree and tell Sora that he's coming with them whether he likes it or not. So he's forced to follow them as they run off. Towards the war. Mickey being Mickey, he's amused by this loophole and rolls with it.
Scias in Breath of Fire IV is a mercenary whose been hired by a minor antagonist to keep an eye on your party, but because he likes finding loopholes in the orders he's been given, he actually ends up assisting the party.
Scias: (On breaking Cray out of prison) He said, if you do anything, I should let him know immediately. He never said I should stop you.
An unintentional example occurs in Dead Rising 2, when Chuck makes a promise that one of the antagonists 'won't leave this city in one piece.' The antagonist in question later ends up as Half the Man He Used to Be.
In Disgaea 2: Cursed Memories, Adell has his mother summon Overlord Zenon, so that Adell can kill him and break Zenon's curse. Instead, they end up with his teenage daughter, Princess Rozalin. They assume Adell's mother botched the ritual in some way. She didn't. The ritual did exactly what it was supposed to do. The problem was that the terms of the ritual were "summon Zenon". They were not "summon the Overlord who's impersonating Zenon."
In Tomb Raider Chronicles, Lara winds up slipping on a slope and nearly falls into a deep pit, but manages to grab onto a ledge and hang on. Her rival, Pierre, arrives and uses this moment to make an exchange; if he pulls Lara up, she will not lay a finger on him. Lara agrees and is helped up, but when Pierre demands the MacGuffin, Lara just gets in Pierre's face and screams "BOO!", startling Pierre and making him slip off the ledge and hangs on for dear life. When he asks Lara to pull him up, Lara replies in a snark manner that they agreed she wouldn't touch him. Lara cheerfully walks away and Pierre falls.
In Final Fantasy XII, Vayne, after transforming into Vayne Novus, orders Gabranth to defend his brother (Lord Larsa) as he'll have much need in "the Hell to follow." Gabranth agrees that he should defend Larsa. Unfortunately for Vayne, he didn't specify who Gabranth was supposed to defend Larsa from, resulting in Gabranth's Heel-Face Turn and eventual Redemption Equals Death.
The ending of Ghost Recon: Future Warrior, has this. The main villain of the game is wounded and ready to be killed by the Ghosts but sudden orders from command reveal that the American Government wants to keep him alive and that he is "not to be touched." The Ghosts are understandably furious, considering the same person was responsible for the deaths of several of their comrades in the opening cutscene and is now taunting them about not being able to take revenge. Moments later a train happens to be coming his way and he pleads to the Ghosts to take him into American custody as per their orders. Their response? "Our orders were not to touch you." He gets splattered by the train and then the credits start immediately after he dies. Poor choice of words.
Saturos uses this trope to his advantage in the end of Golden Sun. When Isaac's party confronts Saturos' party, Isaac's crew demands that Saturos hand Sheba over. Saturos says that if Isaac hands over the Shaman's Rod, Sheba won't be harmed. The rod is given over and Isaac's party complains that Saturos altered the deal. Menardi quips in by saying that they never actually said they would let Sheba go, but that they would not hurt her.
In Dark Souls, Kingseeker Frampt tells the chosen undead that by linking the fire, he or she will succeed Gwyn, the lord of Anor Londo. What he does not tell the player is that Gwyn has been burning alive for centuries. By succeeding him, the undead will face the same fate.
In a puzzle from Mysterious Village, a man has three stinky vials of perfume hooked up to a series of tubes connected to three holes. Unfortunately, he only has two corks, so you need to work out which two holes you should plug to stop him from having to smell the stink. It's his two nostrils; all three of the holes are producing a stink, so there's no way to stop the smell plugging only two of them.
In a puzzle from Miracle Mask, a student is trying to help a small ant cross a bridge of colored pencils. The ant can only climb down pencils; it is too small to climb up again. The challenge is to move only one pencil to make it possible for the ant to cross. You move the pencil the ant is already sitting on, of course.
In Fire Emblem Awakening, the sugar obsessed thief named Gaius says he'll join the player's army if you "sweeten the deal". At first it's believed he wants gold, but he literally meant "sweeten", because he's recruited over a bag of candy.
Assassin's Creed I: Altair is told "The answers you seek will be there when you no longer need to ask for them. Altair isn't asking for them. He's DEMANDING them.
Noel told Ragna at the beginning of BlazBlue: Continuum Shift that the next time they meet they will be enemies. In their next meeting, Noel has transformed to Mu-12 and ready to kick Ragna's ass.
In Knights of the Old Republic II, the Exile makes a promise to Atris that they won't train the Handmaiden in "the ways of the Jedi", something that the Handmaiden's own vows prevent her from pursuing. The Exile later capitulates to the Handmaiden's request for training, pointing out that Atris never said they couldn't learn the ways of the Force, thus neither of them can be said to have broken their word.
Batman: Rise of Sin Tzu. The titular villain has planted what Batman is led to believe is a large-scale bomb within a shipping crate. He takes it back to the Batcave in an attempt to disarm it safely and whilst it does explode, the explosion is fairly small, and only reveals the true contents of the crate.
Batman: Bane?! Bane: He never said "bomb". He said "weapon of mass destruction". And that, is me.
The Witch's House: Early on, you find a sign that reads "LEND A HAND". If you talk to the invisible chef in the next room, you get the chance to "Lend a hand". Choosing to do so leads the chef to grab your wrist... move you to the chopping board and... you get the picture. To actually solve the puzzle, you have to offer the dismembered hands of a teddy bear. That you cut up earlier.
In week 3 of The World Ends with You, the game master challenges the players to a game of hide and seek. The game master will choose one place to hide, and challenges the players to find that spot before time runs out. Despite these terms, Neku keeps hearing the game master's laughter wherever he goes, as he searches all over Shibuya. It's eventually revealed that the "one place" the game master chose was the shadow of Neku's partner. She never said the hiding place had to itself be stationary!
God of War: Athena promised Kratos that his past crimes would be forgiven if he killed Ares and saved Athens. She never said that he would be rid of his nightmares.
In Tales of the Abyss, the Score states that "The young scion of Lorelei's power shall bring his people to the miner's city." It said miner's city, not Akzeriuth.
Tales of Destiny: Hugo never said he'd let Marian go, and he doesn't, even after Leon steals a dragon and the Eye of Atamoni, betrays his friends, and dies to buy him time.