Temporal Paradox / Video Games

Temporal Paradoxes in Video Games.

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Grandfather Paradoxes

• In Achron, paradoxes are a deterministic and fully logical gameplay element that oscillate back and forth between one state and the other as time waves gradually propagate the latest changes along the timeline.
• The flash game Chronotron revolves around the player's ability to travel back to the beginning of the stage (so that multiple version of the player exists at the same time). It is quite possible to either kill a past self, or bar their passage to the time machine - resulting in a time paradox "death", complete with a Penrose triangle warning sign.
• In Day of the Tentacle there are several examples. Thought temporal paradoxes are mostly averted during the main game, where the protagonists are scattered through three periods, some severe paradoxes occur after the second time-travel where the protagonists (and the tentacles) travel to yesterday.
  • The whole point of the plot is preventing an event from happening, thus erasing the need for the time-travel. However it is an essential part of the gameplay that timetravels do affect the present.
  • During the endgame (that is set one day before the present) it is possible to remove the "Help Wanted" sign from the window, that will be picked up from Bernard in the present. Also the bowling-ball should be in a different place.
  • According to the dialogue between the protagonists and Purple Tentacle, the Sludge-O-Matic, what made purple tentacle an insane genius, was invented by himself, who send it back to the present to Doctor Fred. (This makes their heads hurt)
  • Purple Tentacle brings a lot of future versions of himself back to the day before the present. So if one of them get hurt or can't return to the future, this would create some horrible paradoxes.
• The entire plot of Dark Cloud is this. At the end, you have to go back 400 years in the past to erase the origin point of the Dark Genie because he's too strong to beat in the present. Of course, in doing so, you make sure that Seda's wife comes Back from the Dead. This prevents Seda from becoming overcome with fury and dark power and getting possessed by the Dark Genie, removing his motivation to fix it all with time travel. Thus, he never rips a hole in time to get to the present and tell Toan about it. Which means that Toan's village never gets blown up, and hence, Toan never goes on a quest to destroy the Dark Genie. Which means that Seda gets possessed and goes into the present. Which means that he doesn't. Which means that he does. Which means that he doesn't. Which means that he does...
  • Result: There are an infinite number of Sedas who both do and don't Time Travel.
  • Keeping in mind that the last scene shows Toan returning home, it makes you wonder just what he's coming back to.
  • And before you even get to that, there's that whole ordeal in Queens. After the boss battle, Rando breaks the Life Sphere, intending to return 100 year to the past with La Saia so they can get married. Since when is Time Travel defined as a feature of the Life Sphere? We're left with the same problem: if Rando and La Saia get married, La Saia never commits suicide because Rando never got the Life Sphere, resulting in La Saia's ship never being sunk, which should completely remove the Shipwreck dungeon from the game, which would mean that the Turtle was never built, meaning that Toan never did anything in Queens. And without a dungeon to go to, there's no place for the Atla to end up, so the town itself was never destroyed.
    • It's possible Rando was only speaking figuratively; he's saying he wants to do what he should have done that day: marry her and screw what the world thinks.
• Final Fantasy XIV has an interesting case of reverse grandfather paradox in the climax of the story for the final raid segment of the primal Alexander. The player character, Biggs, Wedge, and Cid are caught in a Time Stands Still bubble that freezes them in place while the Big Bad orders Alexander to blast the heroes to bits with a giant laser. At the last moment, the party is freed from the time freeze and dive out of the way. Once you fight Alexander himself, he sends several minions into a portal to be sent back in time and several of your party members need to follow them in order to stop them. You travel back in time to the very moment where your past self was frozen in time and it was the minions that caused the time freeze. By destroying the minions, you become the exact reason why the time freeze was undone and basically saved your past self, creating a Stable Time Loop. However, if you don't destroy the minions fast enough, Alexander's past self successfully kills your past self, which causes a paradox and kills the entire party instantly.
  • Shadowbringers mentions the paradox as a possible fate for Graha Tia, who comes from an alternate timeline where the Garlean Empire wins the war and kills all of Eorzea and the Scions with the Black Rose bioweapon. If he success in altering history, he will vanish since the events would render his travel to the past unnecessary. At the end of the story, he still remains whole and is naturally confused as to how he is still alive.
• Time-travelling in miniature into your own brain can have equally unpleasant results in The Hitchhiker's Guide to the Galaxy (1984) Infocom text adventure. When the minaturisation wears off, you cause the head you're in to explode. You're fine... but you won't be when the miniature you, now inside your own head, expands to full-size...
• inFAMOUS has a character who still exists despite drastically changing his own past. The idea of alternate universes is never so much as mentioned; rather, the character in question travels through time via his own superpower, with immunity from changes in the timeline granted by Required Secondary Powers. Unfortunately, the timeline itself is not immune to his presence, as the sequel will show, creating another Alternate Timeline...
• In Injustice 2, Eobard Thawne, aka Reverse-Flash, travelled back in time to fight the present-day Flash, Barry Allen. Unfortunately, because Superman's Regime had killed an ancestor of Eobard's, he became trapped in the altered Injustice timeline, unable to return to his own time.
• The Metal Gear games are well known for situations occurring in which the player can create a paradox of sorts, by killing someone in a prequel who is known to be alive in chronologically later games. Of particular note is Revolver Ocelot, in the third game, whose death during certain scenes results in an instant Non-Standard Game Over. It's especially surreal when your CO from the future starts chewing you out for causing a Time Paradox.
• Millennia: Altered Destinies has this as a premise. You are given a space/time ship called XTM that can travel to any star in the Echelon Galaxy within a 10,000 years timeframe in 100-year increments. Your ship is shielded from "temporal storms" which occur whenever you change something in the past. You also have a database containing information for each of the planets in the galaxy. Unlike the ship, the database is specifically unshielded, so that you can keep track of any changes you make and their consequences. The goal is to prevent the galaxy from being taken over by the Microids. In order to do that, you have to guide four sentient races from the Stone Age all the way to space travel. You also have an Evil Counterpart, which is you from an alternate timeline, who was recruited by the Microids to keep history from being changed. He/you will randomly appear at different points in time and mess up your efforts. And you can't kill him/you, as he/you will do a Hyperspeed Escape as soon as you show up. Occasionally, during a time jump, you can find yourself in a "green mist", facing an alternate version of you (not the evil one). Whatever you say to him now, he will tell you later, when you enter the "green mist" again. This is a clue to getting the most powerful weapon in the game. Originally, the developers included a Non-Standard Game Over (in the form of a temporal storm that's too powerful for the XTM) which would be kicked off if you messed up the game so bad it can't be fixed. However, they quickly realized that, the way the game is designed, there is no way to reach this situation.
• An Easter Egg in Modern Warfare Remastered allows you to kill Makarov during the assassination attempt on Imran Zakhaev. This would have caused the events of the second and the third games to not happen, given that Makarov becomes the Greater-Scope Villain in those games. Sadly, nothing comes of it.
• In Persona 3, it does have quite a devastating effect - the main female love interest wants to go back in time and save/see the main character before he sacrificed himself, which might bring about The End of the World as We Know It.
• The Ubisoft Prince of Persia trilogy is entirely based around this concept.
  • In Prince of Persia: The Sands of Time, the Prince's father find the Hourglass of Time whilst invading another land's fortress, and the Prince is tricked into releasing the sand within by the evil vizier. This turns pretty everyone except the Prince, the vizier and the princess from this other land (Farah) into sand monsters, leading the Prince on a quest to undo it all. He teams up with Farah, but she dies during the adventure until he manages to get to the hourglass and insert the dagger, reversing everything up to the point where they originally invaded the fortress. Waking up in camp with the dagger he visits Farah and tells he everything, though she doesn't remember now naturally, since it never happened. The vizier enters, but the Prince kills him, then gives the dagger to Farah and leaves, asking her to call him "Kakolookiyam", a word with significance to her that she told him during the adventure together.
  • Cue Prince of Persia: Warrior Within, 7 years later. The Prince is informed by some old dude that he should have died during the first game, but cocked it up through messing round with the time continuum and is now hunted by the Dahaka, a guardian of the sands, which seeks to kill him and restore the balance. To stop this, the Prince decides to travel to the Island of Time to stop the sands ever being created by travelling back through time to kill the Empress of Time. He rescues a woman, Kaileena, and sets about trying to get to the Empress whilst dodging the Dahaka and a strange wraith-like figure seemingly out to get him. Whilst travelling to the Throne room he is confronted by both, but escapes when the Dahaka kills the wraith and buggers off. Kaileena reveals herself to be the Empress; the Prince kills her and travels back to the present, only to be confronted by the Dahaka again, since the sands turned out to have been created by the act of killing the Empress. He almost gives up hope when he discovers the mask of the Sand Wraith, which allows him to co-exist with himself in the same time-line. He then goes back in time, revealing himself to be the strange wraith-like figure, who wasn't trying to kill the prince but in fact save him. When confronting his past self with the Dahaka outside the throne room he dodges the Dahaka, allowing it to kill his old self, which reverts him back to the Prince. Confused yet? He then proceeds to confront the Empress again, but this time throw her through a portal into the present, planning to kill her here, thus still creating the sands, but not in a time frame that would allow them to be found by his father. Then the Dahaka shows up again, now trying to kill the Empress, but together they manage to defeat it and set sail for Babylon, the Prince's home.
  • Which takes us to Prince of Persia: The Two Thrones. Arriving at Babylon they find the place ransacked because by retconning his past the vizier of course never died, got hold of the dagger, and proceeded to attack it, looking for the Sands of Time. Kaileena is captured, but when the Prince tries to rescue her the vizier stabs himself with the dagger, turning into a sand god or something, killing Kaileena and infecting the Prince with the sands. Princey manages to swipe the dagger, though, escape, and set about to kill the vizier again. Along the way he bumps into Farah, who had been captured way back when the vizier got the dagger, and discovers that the sands have manifested within him as the Dark Prince: a separate personality that tries to convince him to look out only for himself. He catches up with the vizier, is soundly beaten and thrown into a well, finds his father, who is dead again, and has a crisis moment where the Dark Prince tries to take over. He resists, fights the vizier again, and kills him with the dagger; Kaileena appears and cleanses him of the sands, and all seems well. Then the Dark Prince pulls him into his own mind and tries to screw it all up but he resists, gets rid of him too and gets the girl. All's well that ends well. Aside from the dead father and ruined city.
• Randal's Monday: By giving Matt his wallet instead of taking it, Randal manages to rewrite the timeline. The demon possessed Sally who came back with Mental Time Travel ends up exploding, killing past Sally, when this paradox occurs.
• In Raidou Kuzunoha vs. The Soulless Army, the villain abuses time travel in order to Set Right What Once Went Wrong... by turning Taisho-era Japan into a world superpower via future technology in a bid to avert the horrid future of Shin Megami Tensei I and Shin Megami Tensei II. It's mentioned that the method he used can only be used freely as a Time Travel device if and only if he abstains from making major changes to the timeline, since his physical existence is tied to that history. As this is fundamentally incompatible with his quest, he uses a loophole, binding his spirit to one of his ancestors; the moment you confront him and break the link, since it's now impossible for the new timeline he's created to end up birthing him, he goes bye-bye into the great Recycling Bin between realities.
• In the Space Quest series of games, Roger Wilco is saved from certain death in Space Quest IV by a mysterious man who is later revealed to be his grown-up son from the future. Roger meets the future mother of Roger Jr. (though she doesn't know it yet) in Space Quest V and if she's killed during the course of the story, Roger Jr. and therefore Roger Sr. as well cease to exist, and it's Game Over. However, in one way to kill off Beatrice picking her up while she's frozen and having her break into bite-sized pieces, you get a slightly different Have a Nice Death message.
• Tales Series:
  • In Tales of Phantasia, Time Travel divides the timeline around halfway through the game in such a way that the object of your characters' revenge and the final boss of the game are two different people. Not only that, but at the end of the game, a sword you acquired in the future is sent back to the past. The character who takes it promises to "seal it away", the concept of "ontological paradox" is apparently entirely foreign to the protagonists.
  • Tales of Destiny 2 is not much better. The party is supposed to be setting time right, but in the process take the Swordians from the past in order to enable Time Travel in the first place, which would severely disrupt events from the first game, and in the end reset time by killing the goddess with the power to travel in the first place. Not only does this cause two party members to stop existing (they end up okay in the end), it may have caused the events of the first game to somehow change by doing so, as implied by the remake's timeline having some drastic changes.
  • The main villains of Tales of the World: Narikiri Dungeon 3 are the main characters from the future, and they are messing up the timeline to unseal the "Demon King Jababa" and defeat him before he can destroy their village. The thing is, the game implies that he got out and destroyed the village because they released him.
• In addition to the ontological paradox (see below), Time: All Things Come to an End also features a subversion of the Grandfather paradox when you relive your childhood memories. You're not in the past to alter history, just to gain important information.
• TimeShift stays light on the plot side, but that doesn't stop the nastier issues from occurring. By the end of the game, the protagonist has been sent back in time and had his time machine damaged by a bomb that later never went off, sent back in time and had his or her time machine damaged by a giant mechanical spider that later was distracted somewhere else at the time and then ceased to exist, can accidentally lead to the death of an individual who earlier would go on to assist the protagonist, was assisted by and provided assistance to capture La Résistance who later never were captured and then were La Résistance to an entirely different matter. All to prevent a time traveling Mad Scientist from replacing 1940s Europe with his own special dictatorship which also prevented the time traveling Mad Scientist and protagonist's time machines from ever being developed. That's before we get to the Wild Mass Guessing that the protagonist survived the bombing once sans timesuit and then went back in time to try to stop the Mad Scientist from ever going back in the first place, or that the protagonist is a time-clone of one of the other characters as implied by the paradox warning triggered by attempting to remove his or her time suit. OWWW!
  • It does strongly note that the Beta Suit cannot ever benefit from the Reverse Time effects, nor can you benefit other people. For example, you cannot use Reverse Time to repeatedly kill/revive someone, your ammo/grenades will never return to you, your health won't restore from bullets never hitting you, and in one case, you cannot prevent someone from being pulverized by stepping into the path of a wind tunnel. You can, however, do some suitably amazing and freaky shit, such as reversing time and shooting from two separate locations simultaneously; once in real time, then reverse time, move to the new location, and open fire once real time kicks in again. The Beta Suit's "mission", however, is to recover the Origin Drive from Krone's Alpha Suit.
• The Infocom Interactive Fiction game Trinity combines this with a Stable Time Loop: Moments before London is destroyed by a nuclear attack, you go back in time to sabotage the original Trinity test and prevent atomic weapons from ever being used.... Unfortunately, as your Spirit Advisor explains, that would change history so that you were never born, thus creating a paradox. The universe, fortunately, resolves the paradox by making a small explosion every time one of the atomic weapons that should not exist is detonated (i.e., destroying a city instead of destroying most of New Mexico as it should) and sends you back to London before the bomb is dropped to do it all over again...
• World of Warcraft has a quest that plays with this. While doing a survey for the Bronze Dragonflight (keepers of time), the player is assisted by his future self. Later on, he needs to do the same thing again to protect his past self. There are also numerous instances which involve traveling through time to either prevent the Infinite Dragonflight (the apparently corrupted future version of the Bronze Dragonflight) from changing the past (the goal of which may finally be becoming clear in the latest expansion, to cause the world to come to an end to prevent it coming to a far worse end later on) or to retrieve things that were lost since great prior events involved them (and, it appears, were lost precisely because you went to get them).

Ontological Paradoxes

• Achron: Pulling off one of these yourself isn't as complicated as it sounds. Usual example: You build a chronoporter (a time teleporter) at a point in time. However, your opponent, who is further in the past than you, destroys your chronoporter. Since chronoporters are expensive and essential to most late-game tactics, you send some units back in time to defend the chronoporter. Instant ontological paradox! The chronoporter only survived because it was defended by units it would chronoport later on. Bear in mind that time travel is fully logical in Achron, so what seems like a paradox makes perfect sense in-game. It's also possible to make a unit literally become its own grandparent/grandchild if you're playing the Grekim.
• City of Heroes: When you first meet Mender Lazarus in the Ouroboros initiation arc, he tells you during a mission fighting Shivans, you somehow knew to destroy the meteor. That mission is the last mission of the arc, and destroying the meteor is one of the mission objectives. Which you know to do because he told you. (Incidentally, that mission is the first time he met you.)
• Dragon Quest V makes use of the Reverse Grandfather Paradox: you travel back time to meet your child self, who keeps a piece of Applied Phlebotinum that would prevent the world from total annihilation. You switch that piece with a fake, knowing that the Big Bad will kidnap your child self and destroy the thingie.
• Final Fantasy XIV has this all throughout the Alexander story line. For example, in the final fight the boss sends several minions into the past to freeze time around your characters before you entered the fight, so he can kill you. Your own party has to follow the minions back and destroy them to break the time bubble around your past self so that you can dodge Alexander's attack. If you fail to stop the minions, you are killed in the past and die in the present.
• The Journeyman Project series works on information paradoxes. The Time Police protagonist is only prompted to go back in time when monitoring devices report historical alterations. Thus, once his mission is completed, there was never a reason to go back in the first place. The only major loophole the series provides is the rule that anything travelling back in time while a temporal overwrite is moving forward (We know, we know) is rendered immune to causality.
• The Legend of Zelda:
  • The Legend of Zelda: Ocarina of Time: Link learns the Song of Storms from a man who claims that he learned it when a kid played that song seven years ago and messed up his windmill. Link then travels back in time seven years and plays the song, messing up the man's windmill. To further compound this, at least from the viewer's perspective, the background music within the windmill is the Song of Storms... even before Link learns the song.
  • The Legend of Zelda Oracle of Ages features a few instances of this due to its extensive use of time travel, mostly involving Link's interactions with the Gorons:
    • In an item trading puzzle, you trade a rock brisket to a goron in exchange for a family heirloom — and then trade the same heirloom to an ancestor of his so that he can hand it down across generations to his descendant who trades it to you so you can trade it to his ancestor who hands it down to him who trades it to you...
    • After defeating the Great Moblin and restoring the gorons' ability to grow bomb flowers, Link is rewarded with a flower of his own. After heading to the past, Link uses this same flower to free goron elder from a pile of rubble. Inspired by this, the ancient gorons take up bomb flower cultivation using the seeds from the flower Link brought back, and as a result end up creating the same crop from which Link will take a flower to bring back to the past.

• Shin Megami Tensei:
  • Shin Megami Tensei IV has you interact with the past to a degree in the DLC missions. By finishing them, you prevent the Archangels from exterminating Past Tokyo and allow Mastema to imprison them in Kagome Tower, from which you spring them in the normal game. Most notably, you have to travel in time just a few hours or minutes after your past incarnation died attempting to convince Masakado to shield Tokyo from the ICBM cluster and defeat him to snap him to his senses, allowing literally all other events in the timeline to unfold naturally.
  • Shin Megami Tensei: Strange Journey has a rather curious form of this. In the second sector, you find a group of Disir whose time-control powers have been stolen by Yggdrasil. They send you to the future to battle him, but since he's so powerful, he'll just utterly curb stomp you with a hearty Evil Laugh. Moments later, as you drift into unconsciousness, another guy pops up in the battlefield and starts hitting Yggdrasil. Moments later, you return to Sector Two, and the Disir tell you the battle's now engraved in your destiny. Fast-forward to Sector Five, and you find yourself in a very familiar battlefield, with a sleeping Yggdrasil, and a destiny goddess who reminds you you have to save yourself before Yggdrasil kills you in the past...
• Sonic the Hedgehog (2006): There are two instances of this.
  • What happened to the blue Chaos Emerald? It starts the game in Elise's possession, but she gives it to Sonic as Eggman abducts her, later receiving the emerald as ransom. Later, Silver finds it in Eggman's base and uses it to travel back in time with Shadow, but the last thing they do with it is give it to Elise... Completely pointlessly, too, since they had just found the gray emerald in the past, so they could have left that one with her instead.
  • Mephiles the Dark decides upon his name when Shadow addresses him by it. Mephiles then goes back 10 years and introduces himself to Shadow, who learns his name. Thus, Mephiles learns his name from Shadow and vice versa.
• Time: All Things Come to an End has the player visit an alternate 1985 where you acquire an aged note and iron sphere (containing a recorded message) from a mysterious man. When you travel back to 1940 you meet a younger version of the man in a Nazi dungeon. To allow your future meeting to occur you must return the sphere to the man and write the note from memory (as you no longer have the original).
• TimeSplitters Future Perfect has multiple examples.
  • Throughout the game, once in every time zone, Cortez crosses paths with a future version of himself, then travels back in time and repeats those events as the future self. The first time this happens is when he is in 1924. He comes across a locked door and is unable to advance. But then, a future Cortez arrives in the hallway above him, and, through a grate, tosses him the key to the door, telling him to pass it on later. When he reaches the hallway above that room, he passes through a wormhole, taking him back in time, and passes on the key to his past self. This leaves one question. Where did the key come from?
  • Another example is when Cortez is in 2052. He enters a large chamber with two terminals and a wormhole. He teams up with three other versions of himself to successfully get through the room. The first and third versions of Cortez hack the terminals, while the second and fourth versions fight off the room's security. However, the two terminals are locked by passwords, which are given to the first and third versions of Cortez by the other two. Just where did this knowledge of the passwords come from?
  • This one is a Reverse Grandfather Paradox. In 2401, the first level of the game, when Cortez is trying to get back to the base with the time crystals, a mysterious figure can be spotted throughout the level, who helps out, especially in the final firefight by sniping enemies from a rock ledge overlooking the base, allowing Cortez to get inside and deliver the crystals, completing the time machine that Cortez then uses to travel though time. Towards the end of the game, when Cortez is in Crow's underwater base in 1924, he discovers that Crow has ordered some assassins to travel to 2401 to kill Cortez before he travels in time. He disguises himself as an assassin and travels with the others, carrying only two weapons, one of them being a sniper rifle. He takes out the other assassins and other enemies blocking his past self's path to the base. Reaching a rock ledge overlooking the base, he joins in the final firefight by sniping enemies, until his past self enters the base.
• World of Warcraft: The key to Karazahn, as found in the present, is beyond the skills of Khadgar to repair and so was taken back in time to be given to Medivh. Due to the damage suffered by the key, Medivh could not immediately repair it, instead giving the player a spare key. The key he was repairing would be given to Khadgar, to continue its trek into the future to be broken and taken back, ad nauseum.

Other

• In the RTS Achron, you can use the free form time travel to create some interesting paradoxes. Apart from the Grandfather Paradox and the Ontological Paradox in many different incarnations, you can create a stable feedback loop to continuously strengthen your army. For example, if 10% of your army survive an attack, you can send these back in time to support their past selves in battle. That way, more units will survive and more units will get sent back in time. Thus, more units will survive. It can also happen the other way around, with your army getting continuously weaker, but that is much rarer and harder to spot. For example if the units you send back in time chronofrag (similar to Tele-Frag) their past selves. Since all players have these abilities, results can get quite unpredictable.
• In Chrono Trigger, one character accidentally paradoxes herself out of existence, forcing you to set things right before history notices. Later you get to do things like take an item from a treasure chest and then go back in time four hundred years and loot its (inferior) temporal duplicate, or in the DS remake combine an object with itself. The characters in-game speculate that some sort of "Entity" or outside force is responsible for keeping all this from getting out of hand, which is convenient.
  • Chrono Cross is a particularly confusing case, involving as it does four, maybe five different factions manipulating an Unwitting Pawn across two dimensions. The Chronopolis research facility attempted a time experiment that ended in a Time Crash, hurling it back in time about fourteen thousand years and forcing it to carefully manage history to avoid any paradox that would prevent its future existence. But then someone meddled in a pivotal event and split the timeline in two, so that in one dimension Chronopolis still exists, while in the other a time-frozen slice of Chrono Trigger's Bad Future has come to fill the void. Also, this may unleash a force that could destroy all of existence.
• Ecco the Dolphin's time paradox consisted of Ecco seeing the Asterite, who tells him to go back in time and recover its missing globe from the Asterite of the past. That means that in the past, a dolphin stole the Asterite's globe, and only because of a request from the future.
• Fallout 2: The player character of this game, the Chosen One, is the grandson of the previous game's PC, the Vault Dweller, who was exiled from his home of Vault 13 after finding a crucial replacement part for its water purification system, on the basis that he had been too changed by his experiences in the wasteland to be allowed back in. On his own quest, the Chosen One has a chance of discovering the Guardian of Forever. Stepping through it, he finds himself in the deserted control centre of Vault 13, and if he should happen to fool with a certain computer, he'll end up breaking the water purification system, thus setting in motion the events that will lead to his birth. As the game itself notes, "this comforts you for some reason".
• Fate/Grand Order: At the beginning of the game, all of human history is wiped out. The heroes are still alive because of some temporal shenanigans they were pulling at the time, noted to be a paradox because none of their ancestors have ever lived. Also, the seven points in time at which human history was wiped out still exist for some reason, meaning you can time travel to them. Fixing those seven alterations to human history allows you to restore the timeline... but that still leaves the matter of stopping whoever did all this in the first place. It turns out that the villain, who is conveniently sitting in a space outside of time, destroyed humanity in order to use their accumulated lives and history as "fuel" to give himself enough power to travel 4.6 billion years into the past, to the point where Earth itself was first formed, and reshape reality in his own image. And since, as mentioned, he sits outside of time, you restoring the timeline doesn't matter: history was still incinerated, and he will still accomplish his goal if not stopped, which would undo all the work you'd done restoring things.
• In Injustice 2, it's revealed that Professor Zoom is stuck in the past because he now exists outside of time thanks to the fact that the Regime killed one of his ancestors and, thus, can't be born. However, since he's so integrated into the Speed Force, he exists basically outside of time.
• Jak and Daxter: At the end of Jak and Daxter: The Precursor Legacy Jak and company find a "rift rider" lying around together with a huge portal. Everyone gets in; they are sent to the future and land in a dystopian city. Keira and her father get away, but Jak is captured and the rift rider is destroyed. Two years pass. Jak II: Renegade starts. When Jak meets up with Keira again, she's working on another rift rider, trying to recreate the one they found from memory. During the game, they meet up with a kid. Eventually Keira finishes the rift rider so they can go home. But it turns out that the Kid is a young Jak, who was born in the future. So Samos has to take him on the rift rider back to the past where he can be raised safe from harm and come back to the future to fulfill his destiny. It turns out that the rift rider Keira built from memory wasn't a replica, but the very same one they found in the past. So they have to go to the past to drop off the rift rider, so past Jak and company can find it and then go through the rift back to the present and— Oh no, I've gone cross-eyed.
  • Daxter sums it up for us:
    (to a very confused Keira) Honey, the more you think about it, the more it hurts the head!
• Kingdom Hearts has time travel rules that establish time travel can only be used for Stable Time Loop plots: all time travel has already happened, and time travelers forget anything they did while not in their proper time once they return home, so it can't be used to retrieve knowledge from the future or past. It is possible to perform a type of time travel that breaks these rules using the Power of Waking, with the result being a paradox where both sets of events happened. The price for this is the time traveler being ejected from reality outright and into a different world that's Mutually Fictional with the world of Kingdom Hearts.
• As part of its recurring themes of You Can't Fight Fate and Screw Destiny, the Legacy of Kain series establishes that time travel always creates a Stable Time Loop, where if you try to change history on your own, the timestream just re-establishes itself as it is meant to be as though you weren't even there, like a river flowing around a stone. The only way to truly alter time is to cause a paradox by bringing the same object or person from one time into close proximity with itself in a completely different time. This creates a disruption in the timeline strong enough to alter history in ways that cannot be predicted, the butterfly effect occurring and history shifting itself around to fit the new chain of events. The main item for this task is the Soul Reaver, due to it being wielded by a variety of powerful figures including the two protagonists, and thus bringing two swords into contact means someone of historical importance is going to die.
  • This mechanic is actually the crux of the entire plot. Because time travel always creates a Stable Time Loop, it means free will doesn't exist, You Already Changed the Past and You Can't Fight Fate—or so it seems. The exception to those rules is the paradox as explained above, and it just so happens that the spectral version of the Soul Reaver that Raziel wields is actually his own soul. He receives the sword in the present, and will travel back in time where he will be drawn into the material version of the Soul Reaver in the past, thereby becoming its spectral half to one day be bonded to him when Kain destroys the material version attempting to kill him. Raziel is walking around with his own soul clinging to his arm, and thus he's a walking paradox, the only person with free will that has the power to change history freely because he creates a temporal distortion wherever he goes. This is why so many people go to such extreme lengths to manipulate Raziel into changing history for them.
  • During the climax of Defiance there's a four-way paradox, with four different versions of the same thing from four different time periods existing in the same time. You've got Past Kain wielding the Soul Reaver that belongs in this time, Present Kain traveled back in time with the original Reaver taken from a point in time further in the past before it became the Soul Reaver, Raziel traveled back in time with the spectral version of the Soul Reaver that was created when the material Soul Reaver currently wielded by Past Kain was destroyed in the future, and Raziel himself who will eventually be drawn into the Reaver wielded by Present Kain to become its spectral half and transform it into the Soul Reaver. Oh, and the Reaver that Present Kain is wielding will also have to be taken back in time at some point after absorbing Raziel's soul so he can leave it for his past self to find and thus leave the timeline up to that point intact. Got all that?
• The Czech-developed RTS game Original War revolves completely around this. 20 Minutes into the Future, just as the world's oil reserves are becoming exhausted, the mineral 'Siberite' that enables Cold Fusion is discovered in Siberia, giving the Russians a monopoly on the new energy source. In order to avoid Russian dominance, the USA uses an alien time machine found during a World War I expedition to Siberia to send volunteers in a one-way voyage to the early Pleistocene, the only period the machine can be set to, and use them to mine and move all the reserves of Siberite to will-be Alaska over a land bridge connecting the two regions at that time. Once there, however, they find Soviet troops from an alternate timeline ready to fight them. The A-Soviets also found an alien time machine in a Siberian archaeological site, along with rests of mining machinery and traces of Alaskite, a mineral that enables Cold Fusion that is only found in Alaska and is threatening to give the Americans the world's energy monopoly, so they used the time machine to send volunteers to the early Pleistocene and move all the reserves of Alaskite from will-be Alaska to Siberia...
• Apparently, bringing a cube from the present to the future in Portal Reloaded violates the laws of causality and creates a paradox, so when you try it, the cube simply disintegrates. Note that you can do the opposite thing: bring a cube from the future to the present. But then, if the present version of that cube is altered in any way, the future cube is Ret-Gone. The player can freely travel between timelines without such problems.
• Radiant Historia has them. Logical, since one of its central themes is Time Travel. One of the most obvious examples is a mission where you talk to a grieving widow, who laments the medicine she got for her husband never arrived till it was too late, leading the party's hero to accept the medicine and give it to the man in the past, causing him to feel better, negating the need for ordering the medicine in the first place. Well, gosh.
  • Stocke is explicitly told early on (though in not as many words) that as the wielder of the White Chronicle, he's a walking blind spot in causality, able to experiment with the timeline paradox-free. Since at least a thousand years of history is littered with Chronicle wielders jumping around to visit key points in their own lifetime that never happened the first time around without the time stream collapsing like an accordion, this is at least internally consistent.
• Ratchet & Clank Future: A Crack in Time's main focus is the Great Clock, which, originally designed to keep time, is being sought out by the villains to ALTER time. Orvus states this would create multiple paradoxes and blow up the universe.
• The Into The Future expansion of The Sims 3 allows you to go into the future. However, by going there, you risk creating one of these, which could erase the sim in question from existence.
• Sonic the Hedgehog (2006) is bnuh guh nyuh gubuh buh... blark... ARGH! Thank God for the Reset Button. Mephiles hates Shadow for sealing him, and attacks when he's freed. Shadow hates Mephiles for attacking him, and seals him. What?!?
  • The Reset Button actually makes the paradox worse. In the original timeline, it's a simple matter of Mephiles getting Hoist by His Own Petard by attacking Shadow too soon in the timeline out of a miscalculated bout of anger, causing the black hedgehog to reject his later offers to rule together and seal him in the Scepter of Darkness. After the Reset, things get much worse, as it causes a Grandfather Paradox when there previously wasn't one, since without Solaris there is no reason to travel back in time, and thus no reason to have stopped Solaris in the first place, causing a need to stop Solaris and so on and so forth.
• Starcom: Nexus contains a really bizarre Reverse Grandfather Paradox. At the start of the game, the starship Byzantium hands some innocuous archaeological artifact to the player's ship. Several hours later, both ships encounter a Negative Space Wedgie and get sent back to slightly different points in time about 12 billion years ago. The Byzantium arrives earlier and gets to participate in a failed rebellion against a rogue AI. Its captain, August Lee, realizes that the player's ship was also sent back in time by the same Space Wedgie; so he decides to create a data crystal containing instructions on how to defeat the rogue AI, and hides that crystal - the innocuous archaeological artifact - on the same planet where he knows it would be found 12 billion years later and handed over by his younger self to the player right before encountering the Space Wedgie. In short, Lee created an object because he remembered handing that object over.
• Stellaris:
  • The Horizon Signal event chain, which centers around something called the Worm-in-Waiting, what your scientists speculate to be a temporal paradox that somehow became "tangled" and sentient. So you get incidents like your newest colony discovering signs that the world was settled by your people ages ago, rebuilding some of those ancient ruins, seemingly doubling in population overnight, only for everyone on the planet to abruptly vanish. Progressing through the event chain can yield some intriguing bonuses in the form of unique technologies like Entropic Recursion and buildings like the Loop Institute, which teaches "a set of social protocols based on paradoxical intuition, and on love," but fully embracing the Worm will leave a permanent mark on your species.
  • One minor event you can encounter is finding a derelict scout ship of an unknown species, just floating dead through space. Then a bit later you come across the same ship, except alive and well and fully crewed. You have a choice at this point: do you warn the explorers of their apparent impending doom, or do you not risk messing with time? No matter which choice you make, they wind up dead anyway.
• Super Robot Wars Reversal's plot. In the future, the world is turned into a Crapsack World. Chance encounter with Duminuss causes Raul/Fiona to be thrown back to the past, before the world goes gloomy. At that point, he/she decides to screw the bad future and make paradoxes here and there, incidentally making the future brighter when they come back in their own time.
• Tales of Phantasia and its sequel Narakiri Dungeon 1 are even more confusing.
  • In Phantasia, it works like this: Trinicus Morrison sends Cress and Mint 100 years back in time to acquire the power (magic) needed to defeat Dhaos, since they couldn't get it in the present (nevermind the fact that Dhaos was literally about to waste the lot of them with his lazers). In the past it turns out that the reason magic didn't exist in the "present" was because its source withered and died, so it's less "get magic" more "keep magic from dying". They succeed but wind up getting drafted to help out in a war against Dhaos, and during said war Edward Morrison (ancestor to the guy that sent you back in the first place) sacrifices himself to prove to one of your party members that Dhaos's methods are evil. Problem is, according to history and the opening cutscene-battle-thing Edward was one of the people who fought Dhaos in the past and forced him to flee to the "present" where he got sealed; with him dead, history would be pretty much fcuk'd, so the party takes it upon themselves to engage Dhaos in the past (with Arche taking the place of Edward and Cress and Mint taking the places of their respective ancestors). Dhaos flees through time like he was supposed to after that, and after finding the time machine the party returns to the "present" at the point right after Trinicus sent Cress and Mint back twenty-seven hours ago.

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