Plot twists are the basis of a great many memorable moments in any type of fiction. Moments where something entirely unexpected throws everything the audience knows into question and signifies a major new turn for the story are some of the most powerful in any work of art.

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Some twists aren't signaled with an explosion, a surprise appearance, or a great event. Instead, a single line serves to throw a wrench in the plot, a handful of words bringing the audience to a complete stop. There are plenty of these lines in video games, many of which are beloved as shocking moments in their games' stories.

10 "Actually...Why Do We Have To Leave Right Now?" - Wheatley, Portal 2

Wheatley becomes corrupted by power in Portal 2

Throughout the first part of Portal 2, the player is aided by the slow-witted Wheatley as they attempt to escape the crumbling Aperture Science laboratory and survive the cruel attentions of the resurrected GLaDOS. To that end, they hatch a plan to replace GLaDOS with Wheatley, giving him control.

Wheatley begins to enjoy the control he has over the facility as Chell rides the elevator to escape, laughing at how small everything else seems. Then, he begins to lower the elevator again with the above quote, signaling his shift to the game's main antagonist and forcing Chell and GLaDOS to put aside their differences to escape.

9 "The Giants Called Me...Loki?" - Atreus, God Of War

Atreus learns that he is Loki in God of War game

Some plot twists take place in the very denouement of their story, forcing the player to recontextualize everything that's come before it. In God of War, Kratos and Atreus are menaced by the Norse god Baldur, driven to despair by his inability to feel anything and hunting for Kratos' deceased wife.

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The game's final boss fight sees Baldur become vulnerable after scratching himself on Atreus' mistletoe arrowhead, leading to his death. This seems to take things in a different direction from the myth until Atreus and Kratos learn that, in the prophecies of the giants, Atreus is called "Loki." This reveals that the entire game has been a reinterpretation of Norse mythology and that they have just brought about Ragnarok.

8 "I Am Sovereign." - Sovereign, Mass Effect

Sovereign speaks to Commander Shepard on Virmire in Mass Effect

For the first two acts of Mass Effect, the villain appears to be the rogue Spectre Saren, using the technology of a long-vanished alien race known as the Reapers to attempt to bring them back. On Virmire, however, Shepard and his team accidentally activate a communications interface to Saren's ship - only for the ship to talk back with full sapience.

In the opening exchanges, the truth of the situation becomes clear. Saren isn't the villain, merely a tool used by the Reapers to bring about their return, with Sovereign pulling the strings all along.

7 "You Are A Templar." - Haytham Kenway, Assassin's Creed III

Haytham Kenway inducting Charles Lee into the Templars in Assassin's Creed III

Although the series drips with moral grayness, for the most part players control heroic assassins in the Assassin's Creed franchise, battling against corrupt and totalitarian Templars who want to put the world under their thumb. This appears to be the case in the early hours of Assassin's Creed III, with the player given no reason to believe Haytham Kenway is anything other than an assassin.

Kenway fights like an assassin, speaks of his brotherhood, and acts like a typical protagonist. It's only when inducting Charles Lee into his order that he reveals his brotherhood to be the Templars. This throws the game's entire prologue into perspective and sets up the father-son battles between Haytham and Connor.

6 "Ulfric Stormcloak: Status - Asset (Uncooperative), Dormant." - The Elder Scrolls V: Skyrim

Jarl Ulfric Stormcloak from the Elder Scrolls V: Skyrim

Sometimes a line doesn't need to be spoken aloud to massively impact the story, In Skyrim, the civil war between the Imperials and the Stormcloaks is the most prominent plotline after the threat of Alduin. The rebels, following Ulfric Stormcloak, fight against the Imperials due to the reforms they've put in place to appease the totalitarian Aldmeri Dominion.

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In the Thalmor Embassy, the player can find a note regarding the Stormcloaks' leader, revealing him to be a tool of the Dominion being used to weaken the Empire and destabilize Skyrim. This has serious ramifications on the civil war questline, and shifts the balance of morality between the two factions severely.

5 "That's 'Cause They Have." - Abby Anderson, The Last Of Us Part II

Abby Anderson kills Joel Miller with a golf club in The Last of Us Part II

In its early hours, The Last of Us Part II seems to be a story about Joel Miller attempting to reconcile with his adoptive daughter Ellie Williams years after she learns that he sacrificed a chance to cure the Cordyceps fungi and potentially save the world in order to save her life. One line in the early game changes the story's entire course.

Joel aids survivor Abby Anderson, returning to her camp with her, where his brother introduces the two of them. Joel comments that the group is acting like they've heard of them. Abby responds that they have, before shooting him. With one line, Abby sets up the game's cycle of revenge, ending any chance of reconciliation between Ellie and Joel.

4 "I Am....Your Son." - Shaun, Fallout 4

Shaun as Father in the Institute in Fallout 4

The main plot of Fallout 4 follows the Sole Survivor on the trail of their kidnapped young son, eventually tracking him down to the sinister Institute, known for replacing inhabitants of the Commonwealth with the android Synths.

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The Sole Survivor has to undergo a lengthy series of tasks to teleport into the Institute, where they come face to face with "Father," the organization's leader. When they do, however, he reveals that he didn't kidnap Shaun: sixty years have passed since the kidnapping, and Father is Shaun. This calls the entire story into question, the player having spent hours chasing ghosts.

3 "Even The Combined Power Of The Jedi Council Couldn't Completely Destroy Your Former Identity, Could It, Revan?" - Malak, Star Wars: Knights Of The Old Republic

Darth Malak from Star Wars: Knights of the Old Republic game

Throughout Star Wars: Knights of the Old Republic, the player hears plenty about Revan, the former master of villain Darth Malak, who was killed by a Jedi strike team before he could dominate the galaxy. The story has them follow in Revan's footsteps around the galaxy, hoping to discover Malak's secret weapon and put an end to it - while more and more things begin tying the protagonist to Revan.

When the player confronts Malak, he reveals why the two seem intertwined. With a single sentence, he reveals that the protagonist is an amnesiac Darth Revan, their mind wiped by the Jedi. The twist has since become one of the most famous in gaming.

2 "Powerful Phrase. Familiar Phrase?" - Andrew Ryan, Bioshock

The Would You Kindly? Wall in Bioshock

Some of the most powerful plot twists don't just take the story in a whole new direction, but also change the very thing the story is about. Bioshock, for most of its playtime, seems merely like a high-quality shooter that satirizes and explores the philosophy of Objectivism as the player prepares to kill Andrew Ryan, the leader of Rapture, at the behest of their ally, Atlas.

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When the player character confronts Ryan, however, he gives them several orders with the phrase "Would you kindly?", which they are forced to obey. He then says the above line, leading to several flashbacks of Atlas saying the same thing throughout the game and the player obeying without question. It not only reveals Atlas as the game's true villain but sets Bioshock up as a masterful deconstruction of linear video games.

1 "Halo Doesn't Kill Flood. It Kills Their Food." - Cortana, Halo: Combat Evolved

Cortana reveals the truth about Halo to Master Chief in Halo: Combat Evolved

The very first game in the Halo series isn't short on plot twists, going from a story about a supersoldier battling dogmatic aliens to a fight against a zombie alien menace on an alien superstructure. However, the biggest twist comes when the player learns what the true purpose of the titular Halo is.

After two missions spent attempting to activate Halo to wipe out the Flood, Cortana tells the Master Chief what Halo really does: kill all sentient life in the galaxy to stop the Flood taking hosts. This immediately changes the game's plot and makes things far more complex, as Chief and Cortana attempt to fight the Covenant and the Flood alongside Halo's Sentinel guardians.