''For who's sake would you destroy everything?''

''Would you kill someone for the sake of everything else?''

A 2012 sci-fi VisualNovel created by Regista and published by Yeti, it is the work of Takumi Nakazawa (of [[{{Never7}} Infinity]] [[{{Ever17}} series]] [[{{Remember11}} fame]]), and written by Souki Tsukishima.

The story takes place in September 2030. In this world, psychic powers have been scientifically proven to exist, with psychics suddenly being born all over the world starting in 2014. This power is known "Beyond Communication", which functions as a form of telepathy, and people with this power are known as "Communicators". A particularly large concentration of Communicators is located in Rokumei City, an academic city with practically unlimited freedom for scientists to research whatever they want, making it a popular spot for them. However, the city itself has very strict security laws, and residents are not allowed to leave the city except under very certain circumstances and conditions.

The game is divided into two routes: [[JustForPun Root]] A, and Root B. Root A tells the story of Watase Kasasagi, the leader of a rescue team group named "SIRIUS". On September 16th, 6:16 A.M., an emergency occurs in the "6th Laboratory of Atomic and Biological Organization", nicknamed LABO, and SIRIUS is sent to deal with it. While there, Watase suddenly comes across two people locked in a fight. Overcome with intense pain and an indescribable fear towards them, he runs away, only to black out in a hallway. When he wakes up, he is greeted by his subordinates, Vice-Captain Kazami Tachibana, and new recruit Jun Moribe. However, he realizes he has lost his memories. As it turns out, LABO has been completely sealed off from the inside, and the LABO itself is full of radiation due to a meltdown. Despite this, Watase decides to take action and continue the search for any remaining survivors in LABO...

Root B tells the story of Natsuhiko Tenkawa, an OrdinaryHighSchoolStudent who is a Communicator. He, along with two of his friends, Mashiro and Louise, rush into LABO the day of the incident, only to hear the explosions, remarking that they're "too late". Natsuhiko's group goes down to the basement floors to see if they can do anything, only to be stuck in a fiery hallway. They run out and find a clear hallway, when all of the sudden, Natsuhiko sees his childhood friend Yuuri (who lives at his house) standing in the hallway. They don't get to talk long before Natsuhiko notices an explosion about to occur, and grabs Yuuri. He then finds himself trying to escape LABO while repeatedly experiencing flashbacks of the 6 days prior to the incident...

When both routes are cleared, they unlock the final two routes, Root C and Root D, which answers the game's many mysteries and provides the conclusion to the story.

Root Double is unique amongst VNs in that it doesn't have a traditional choice system where the player chooses between one or two prewritten options. Rather, it uses a system known as the "Senses Sympathy System". With this system, the player is occasionally prompted to adjust an Enneagram graph, which shows the protagonist's trust levels with other characters and themselves. By adjusting the trust levels, they can change the outcome of various events in the story, determine whether or not you avoid a Bad Ending, and whether you head for a Good Ending or the Normal Ending.
----
This game provides examples of:

* AbusiveParents: [[spoiler:Yuuri's]] parents, who would always fight with each other and get angry at [[spoiler:Yuuri]] over the slightest things.
* AccidentalMurder: [[spoiler:In one of Root A's Bad Endings [[spoiler:Watase and the others are fighting over who gets to keep a gun. If Watase suggests he takes it, then they all wrestle for control of the gun until it ends with Ena accidentally shooting Watase.]]
** [[spoiler:Later, in Root A's Normal Ending, Watase is fighting Louise when Louise tries to reach for an axe. Watase then tackles her to prevent her from doing so, which sends her flying towards a generator and smashing her head on it, killing her.]]
* ActionGirl: Kazami, Jun.
* AlliterativeName: [[spoiler:Alice Anfram, the first S Class Communicator. By the Epilogue, Kazami is also an example, now being "Kazami Kasasagi".]]
* [[spoiler: AmnesiacDissonance: Averted- when Watase recovers his memories and remembers he was one of the terrorists who caused the incident, he goes back to his former alignment. Fortunately, since he was more of a WellIntentionedExtremist than anything, he still is willing to help Natsuhiko out, just on his own terms.]]
* AngstComa: [[spoiler:As a kid, Natsuhiko]] fell into one for three months after learning about [[spoiler:Yuuri's death]]. By the time he woke up, [[TraumaInducedAmnesia he'd repressed those memories]].
* AssholeVictim: [[spoiler:Dr. Eriguchi, who was a corrupt doctor who experimented on humans freely, and is who made Nagisa into who she was.]]
* BigDamnHeroes: [[spoiler:Ena comes just in time to save Natsuhiko, Yuuri, Ukita, and Mashiro from a BC corrupted Jun.]]
** [[spoiler:Near the end of Root D, when the group (minus Watase, Natsuhiko, and Yuuri) rush out the gate to the entrance of LABO, Miyoko has roused the remaining rescue team members to restrain the members of Security 6th Division, preventing them from capturing the group.]]
* BittersweetEnding: [[spoiler:Root B- Natsuhiko has made peace with Yuuri's death, apparently has gotten Mashiro to safety, and manages to successfully fight off Watase and destroy his mind. However, he's left bleeding to death in Area N, and the events of Root A are only just about to begin.]]
** [[spoiler:Root D's Good Endings: The After Ending has Natsuhiko take Yuuri's place in going to "Q" with Watase, and via his Senses Sympathy, she starts to delude that Natsuhiko is still at his house, much like he did with her earlier. However, Mashiro and Louise tell her the truth, and she vows to save Natsuhiko.]]
*** [[spoiler:The Before Ending has Natsuhiko erase all of Watase's memories in order to save Yuuri. Watase wakes up a few days later in a hospital to find Kazami and Jun over him, but he runs when he sees black suited men (probably from "Q") after him. He runs into Ena at the lobby, who sends her men to protect him, and then tells him his past, with Watase thinking that "it's not over yet."]]
** [[spoiler: Also, all of Root D's Normal Endings, in which three characters stay behind in LABO (Watase, Kazami, and Jun in A, Natsuhiko, Watase, and Ukita in B, and Natsuhiko, Yuuri, and Kazami in C) and sacrifice themselves so that the other six may survive (though A hints that those three may have survived).]]
* ChainsawGood: In the late parts of [[spoiler:Root A, when Jun]] goes through her SanitySlippage, she starts hunting down her enemies using an engine cutter (which is essentially a specialized chainsaw).
* ChekhovsBoomerang: [[spoiler:The air tank, after its failed attempt at usage in Root A, is reused again at the end of Root D, where Watase uses it to escape through the pipe with Natsuhiko and Yuuri (after having successfully destroyed the obstacle in the pipe.]]
* ChekhovsGun: [[spoiler:The air jack and the engine cutter, which are used to free Watase and Yuuri when they get trapped under rubble. The air tank and the heatproof suit are subversions- while Watase does use them in his plan to try to escape LABO, that plan ends up failing.]]
* ChekhovsLecture: [[spoiler:Nearly all of Ena's lectures about speculative functions of BC end up coming into play at a later point.]]
* ChekhovsSkill: The fighting move that Louise teaches Natsuhiko ends up saving him from [[spoiler:Watase.]]
* CooldownHug: [[spoiler:In Jun's additional scene near the end of Root A, Watase tries this to stop her rampage. It fails, but it turns out her target isn't Watase anyway, so she leaves him alone.]]
* TheCorruption: [[spoiler:Nagisa, who uses her Senses Sympathy ability to corrupt people's memories and fill them with malice, turning them into murderous, hate-filled people.]]
* CreepyChild: [[spoiler:Nagisa, who, after having been forced to see 351 different people's memories, has become a being full of malice who delights in corrupting the minds of anyone she comes across.]]
* CryForTheDevil: [[spoiler:As Natsuhiko encounters more fragments of Nagisa in different people's minds, he feels more and more sympathy for her each time, to the point that by the end, he wishes there was a way he could have saved her. In fact, one of the scenes where he talks to one of her fragments is named "Sympathy For The Devil".]]
* CursedWithAwesome: [[spoiler:Level S Potential Communicators can project their thoughts and feelings onto other people, read their minds, and can basically hijack their brains and see their memories, erase/add memories and change their feelings... but at the price of having a short lifespan of 20-30 years.]]
* DeadAllAlong: [[spoiler:Yuuri, who turns out to have died in the accident in LABO 9 years ago, and the "Yuuri" that Natsuhiko sees is just a delusion he created from his PTSD after the incident, being unable to accept her death.]]
** [[spoiler:This is eventually subverted, where we find out that Yuuri survived the incident, but was secretly taken by LABO, who used her as an experimental subject for BC.]]
* DeathByChildbirth: [[spoiler:Alice, who died giving birth to Louise.]]
* DefectorFromDecadence: [[spoiler:Ukita, who joined "Q" because he couldn't stand the fact that LABO was conducting human experimentation.]]
* DefrostingIceQueen: At first, Louise starts off as rather cold, but thanks to Mashiro, Natsuhiko, and Yuuri, she opens up a lot more to them.
* {{Determinator}}: Watase, big time. [[spoiler:The guy was willing to run into a room where there's a (supposed) melted down nuclear reactor and put out the fires just so everyone else could escape.]]
** Natsuhiko as well. [[spoiler:He gets shot four times, and yet still manages to keep running through LABO, fight off Watase for a brief time, and still manages to concentrate enough to use his BC abilities to destroy Watase's mind.]]
* DisappearedDad: Natsuhiko's father died when Natsuhiko was five years old.
* DownerEnding: The Bad Endings, naturally.
** [[spoiler:Root A's Normal Ending. Everyone except Watase dies (Mashiro isn't found, but her corpse is reported later), Watase, who has pretty much lost any sanity he had, falls into a coma, and Miyoko is left wondering exactly what happened down in LABO.]]
* DrivenToSuicide: [[spoiler:Kazami in Root D Bad Ending #6.]]
* DyingAsYourself: [[spoiler:When Natsuhiko destroys the final fragment of Nagisa (in Kazami's head), Nagisa appears to Kazami in her mind as her old, uncorrupted self, saying one last goodbye to her and telling her not to blame Watase and Ukita for her death.]]
%%* EarnYourHappyEnding
* [[spoiler:EverybodyLives: With the exception of Nagisa.]]
* {{Expy}}: WordOfGod says that aspects of Watase were based off of Takeshi Kuranari from {{Ever17}}. [[spoiler:His backstory, motives, and post-amnesia personality shift are also heavily similar to Satoru Yukidoh's from {{Remember11}}.]]
** [[spoiler: Likewise, both Wataru and Nagisa are Expies of Sayaka Yukidoh from the same game.]]
* FakeMemories: [[spoiler:Watase's memories in Root A of what happened before his amnesia are all fake memories based off of Natsuhiko's memories of the events he experienced.]]
** [[spoiler:This is Nagisa's favorite method of corruption- altering people's memories to fill them with malice, driving them into a murderous rage.]]
** [[spoiler:It turns out that Yuuri did this to Louise just before the start of Root B, modifying Louise's memories to hide her history as a test subject (as part of an agreement between Louise and Miyoko so that Louise could leave LABO and live freely outside).]]
* FakeOutFadeOut: [[spoiler:In Root A's Good Ending, it looks like Watase will sucessfully escape LABO, with the credits rolling... then it suddenly comes to a halt as he comes across something blocking him, and the route continues on for a while longer.]]
** [[spoiler:Repeated in Root B. Having finally come to terms with Yuuri's death and having made peace with Mashiro, Natsuhiko takes her hand as they go to escape. The credits roll... but at the very end, Mashiro is shot by Watase, and the route continues.]]
* FantasticRacism: There's a lot of discrimination against Communicators from the normal populace.
* FiveManBand: Root A's cast, although the first two roles tend to fluctuate due to Watase's amnesia.
** TheHero- Watase/Kazami
** TheLancer- Kazami/Watase
** TheBigGuy- Jun
** TheSmartGuy- Ukita
** TheChick- Yuuri
** TheSixthRanger- Ena
* {{Foreshadowing}}: [[spoiler:When Natsuhiko calls Yuuri on the 15th, for a split second, you can very briefly hear Natsuhiko's answering machine answering at the same time as Yuuri.]]
** [[spoiler:Memories that have parts of them corrupted by Subject N are noted by the scent of flowers. In Jun's flashback, she mentions that both her and Nagisa loved the smell of flowers at the flower shop Kazami worked at.]]
* ForScience: [[spoiler:The reason Yuuri was experimented on was to study the effects of various BC processes that Level S potential Communicators could use (including Senses Sympathy). However, unlike most cases, thanks to Miyoko watching over her, Yuuri was not treated inhumanely during this time. Nagisa, on the other hand... was not so lucky.]]
* FunWithAcronyms- The acronyms "A.D." and "B.C." appear very frequently in the game for various things.
* GenderBlenderName: [[spoiler:Wataru, Watase's older twin sister, who's name is almost always used for boys.]]
* GenkiGirl- Jun, Mashiro, [[spoiler:Wataru]].
* GetOutOfJailFreeCard: [[spoiler:Watase is released from jail in the Epilogue in exchange for selling out the other members of "Q".]]
* GoOutWithASmile: [[spoiler:Nagisa.]]
* GoldenEnding: The True Ending.
* GraveMarkingScene: [[spoiler:Watase's side of the epilogue ends with him, Kazami, Jun, Ena, and Ukita visiting Nagisa's grave.]]
* HalfIdenticalTwins: [[spoiler:Watase and Wataru, the latter who looked almost exactly like Watase (minus the white strand of hair).]]
* HappilyMarried: [[spoiler:Watase and Kazami in the Epilogue.]]
* HeelFaceTurn: [[spoiler:Watase in the True Ending.]]
* [[spoiler:HellishPupils- Those who have their memories and feelings corrupted by Nagisa display these.]]
* HeroicBSOD- [[spoiler:Watase]] falls into one after [[spoiler:Ena's death]] in Root [[spoiler:A's Normal]] Ending, and it only gets worse from that point onwards.
* HeroicSacrifice: In Root [[spoiler:D Normal Ending 3]], [[spoiler:Kazami]] does this, using her body as a shield to protect [[spoiler:Natsuhiko and Yuuri]] from rubble.
* {{Hikkikomori}}: Rare female example- Yuuri never leaves Natsuhiko's house due a fear of the outside world [[spoiler:caused by her getting caught up in the accident in LABO along with Natsuhiko nine years ago.]]
** [[spoiler:As Yuuri is actually dead (supposedly), the actual reason for this is revealed to be that Natsuhiko's delusional Yuuri refusing to go outside was his desire to keep her in the house forever so she'd never be in danger, stemming from his supressed regret of taking Yuuri with him to LABO, which caused her death.]]
* HopeSpot: In Root A, [[spoiler:after the group's had an emotional moment, are getting along great, and look like they're finally about to escape via a lift that goes to the upper floors, they head to the lift... only to see the corpse of a young girl and that the lift control panel is broken.]]
** [[spoiler:At the end of Root A, Watase and Kazami come up with a plan to escape, via getting out through some pipes that leads to a nearby lake. They work everything out, share a kiss, and Watase goes to escape... only to find that the pipe is blocked, forcing Watase to get back. It only goes downhill from there.]]
* HowWeGotHere: Root B opens with Natsuhiko's group arriving at LABO on September 16th just as the incident occurs, and the rest of the route is devoted to showing how they ended up there over the last six days.
* IdenticalGrandson: Natsuhiko pratically looks like a male version of his mother, minus the ponytail.
** [[spoiler:Louise looks like a younger version of her mother, Alice.]]
* ImColdSoCold: [[spoiler:Kazami's]] last words in the Root [[spoiler:A Normal]] Ending.
* ItWasHereISwear: When [[spoiler:Watase]] finds [[spoiler:Yuuri's]] body, he goes and tells the others, then goes back to where he found the body... only to find that it's gone. None of his companions believe him, dismissing it as a hallucination on his part.
** [[spoiler:Which it turns out that it actually was- it was a fake image that Natsuhiko created to distract Watase.]]
* JourneyToTheCenterOfTheMind: [[spoiler:Using his Senses Sympathy ability, Natsuhiko dives into Watase's mind to reconstruct his memories (and at the same time find out the reason he became a terrorist). This eventually turns into him doing this on everyone who's been corrupted by Nagisa, purifying their memories.]]
* KillEmAll: [[spoiler:The Root A Normal Ending, which ends with everyone except Watase dead.]]
* LaserGuidedAmnesia: Watase. [[spoiler:This was caused by Natsuhiko, who, by using his BC powers, literally destroyed Watase's mind, causing him to forget everything.]]
** [[spoiler:It turns out that in the past, Yuuri, upon Miyoko's request, tried to do this to Natsuhiko while he was in his coma by deleting all of his memories of Yuuri (in an attempt to get him to awaken from his coma). However, when she got to the last memory, Yuuri broke down and couldn't go through with it, and so gave him back all those memories.]]
* LaughingMad: [[spoiler:Watase]] in the Root [[spoiler:A Normal]] Ending.
* LeeroyJenkins: Depending on your choices in the SSS, Watase can end up performing these actions, most of the time which [[TheManyDeathsOfYou ends up killing him]].
* LoveMakesYouCrazy: [[spoiler:Natsuhiko]] is ''very'' willing to mess around with [[spoiler:Watase's memories]] if it means keeping [[spoiler:Yuuri safe. Yuuri]] eventually calls him out on this.
** LoveMakesYouEvil: [[spoiler:In Root D Bad Ending #3, Nagisa, using her malice, manages to corrupt Natsuhiko into this, causing him to destroy Watase's mind and shoot him in the head.]]
* ManOnFire: Many of Root A's Bad Endings feature this.
* MeaningfulName: The kanji in Natsuhiko's first name, combined with the second kanji in Yuuri's first name, form "Natsuhikoboshi", another name for Hikoboshi, the Japanese name for the star Altair, which is a significant star in Tanabata(in-universe, Tanabata was the day when [[spoiler:Natsuhiko and Yuuri got trapped in LABO nine years ago, and, for the next nine years, is the only day of the year Yuuri is able to see Natsuhiko)]].
* TheMole [[spoiler:Ukita is one for LABO, as he is actually a member of Q working towards taking down LABO.]]
* MonsterSobStory: [[spoiler:Nagisa, who, while having no qualms about corrupting people's memories and states she can never be changed, still was forced to become what she was against her will.]]
* MyGreatestFailure: [[spoiler:Natsuhiko feels extremely guilty for getting Yuuri caught up in the LABO accident nine years ago, which is why he's so protective of her and so different from his personality as a kid.]]
** [[spoiler:The true reason behind all this is that Yuuri actually died during the accident, and Natsuhiko, who has repressed his memories of it, is so different because he subconsciously doesn't want to get anyone else killed.]]
* NamesToKnowInAnime-
** Creator/AiShimizu- [[spoiler:Subject N (Nagisa Tachibana)]]
** Creator/AsamiImai- Mashiro
** Creator/KaoriNazuka- Yuuri
** KeiShindou- Louise
** Creator/MegumiToyoguchi- Ena
** Creator/MitsuhiroIchiki- Natsuhiko
** Creator/RinaSato- Kazami
** Creator/SayakaOhara- Miyoko Tenkawa
** Creator/ToruOkawa- Ukita
* NiceJobBreakingItHero- [[spoiler:Natsuhiko creates the fake image of a dead Yuuri to divert Watase from remembering his hatred towards Communicators, but this ends up leaving him very suspicious, as this occurs at the same time the AD vials are stolen, making Watase the prime suspect and turning everyone against him.]]
* NotGoodWithPeople: Louise, who has a very hard time understand other people's emotions and their changes in emotions. At one point, she likens it to how normal people can't understand insects' emotions. [[spoiler:Justified, as the entire week of Route B is the first time in her life she's ever interacter with others apart from Miyoko.]]
* OfficialCouple: [[spoiler:Watase/Kazami.]]
* OnceMoreWithClarity: The game ''loves'' this trope, with many scenes in earlier routes shown again later on with different context.
* OneDegreeOfSeparation- Kazami and Jun are very close friends (their families were close), [[spoiler:Watase and Kazami used to date, Watase was the one who saved Jun from a fire]], Ena is Louise, Natsuhiko, and Mashiro's teacher, Yuuri lives/is childhood friends with Natsuhiko, who is childhood friends with Mashiro, a distant relative of Louise's [[spoiler:(not really)]], and the neigbor of Ukita, who works at the same facility as Natsuhiko's mother... yeah, virtually everyone is connected to each other from at least one other person.
* OneSteveLimit: Averted- The name given to Louise's robot ferret, Alice, coincidentally happens to be the name of the [[spoiler:Communicator who accidentally caused the mass arson incident 16 years prior to the story (and is Louise's mother).]]
* OrdinaryHighSchoolStudent: Natsuhiko.
* ParentalAbandonment: [[spoiler:Yuuri's]] parents died in an accident a while back, which is why [[spoiler:Yuuri started living with Natsuhiko.]]
** [[spoiler:However, this is a subversion- this is how the PTSD-afflicted Natsuhiko chose to remember things to fit his delusion. In reality, Yuuri's parents moved out of the city after her death, having no more reason to stay there.]]
* ParentalNeglect: [[spoiler:Jun's]] parents.
* PermaStubble- Watase.
* PoliceAreUseless: [[spoiler:When Mashiro uses Empathy to read a terrorist's mind and learns that he plans on doing something terrible, she contacts the police upon Natsuhiko's suggestion, but they refuse to believe her (because they can't believe that a terrorist would open their mind up to anyone and be suspectible to Empathy).]]
* PoorCommunicationKills: Had [[spoiler:Louise]] known that [[spoiler:Watase had truly lost his memories]], a lot of the conflict towards the end of Root A could have bee avoided.
* ThePowerOfTrust- The SSS revolves around this- the more trust you put into a person, the more likely you are to take their side in a situation (though a certain amount of trust is required in the protagonist as well.)
** Like the example in StupidityIsTheOnlyOption, Yuuri lampshades the importance of this need for trust in Root B, telling Natsuhiko not to doubt the ones around him.
* PsychicPowers- Communicators, though said powers are limited to forms of telepathy. However, it's played with in that a lot of Communicators are actually fairly bad at BC (requiring lots of practice), and those who can use it properly are rare. This limit is lampshaded when Watase asks if they have powers like teleportation, only for Ena to rebuke him.
** Specifically, the Communicators of the group are Natsuhiko, Mashiro, Yuuri, Louise, [[spoiler:and Kazami.]]
* ReallyDeadMontage: [[spoiler:Yuuri, Ena, and Jun (the latter two in the Normal Ending only) in Root A, though in Yuuri's case, it becomes doubtful whether or not she actually "died" once her body disappears.]]
* RelationshipVoiceActor: Akane Tomonaga (Jun), Creator/MegumiToyoguchi (Ena), and Shunsaku Nishigaki (the commander of Sirius) all played roles in one of the director's former works, {{Remember11}}.
* RestrainingBolt: [[spoiler:Watase's blackouts]] turn out to be a version of this- [[spoiler:Natsuhiko's consciousness, while in Watase's body, uses his BC powers to knock out Watase when Natsuhiko thinks Watase is going to hurt one of his friends.]]
* SanitySlippage: [[spoiler:Ukita and Jun]] go through extreme degrees of this in the later parts of [[spoiler:Root A]], each one of them becoming willing to kill. [[spoiler:Watase]] also suffers this in the [[spoiler:Root A Normal Ending]], and [[spoiler:Kazami]] descends into this after [[spoiler:Louise]] reveals that [[spoiler:Watase]] may be a terrorist.
** [[spoiler:It turns out all of these (with the exception of Watase) were caused by Nagisa's influence, who corrupted them with her Senses Sympathy ability.]]
* ShadowArchetype: [[spoiler:Nagisa is pretty much what Yuuri would have become had Miyoko not been the one to take charge of her care while she was in LABO.]]
* ShoutOut:
** At one point, Kazami (the calm, collected, purple haired woman of the group) gets impaled in one of her calves by a metal pipe... [[{{Ever17}} sound familiar?]]
** In Root B, Mashiro buys some Regista Gold (a fictional drink mentioned in [[InputOutput I/O]]).
** Mashiro names Louise's robotic ferret "Alice", after the sci-fi author Alice Sheldon (who used the penname James Tiptree Jr.), as Louise was reading one of her books.
** In Root B, there's a member of the music club who uses Telepathy to try to sing so everyone in the school can hear him. One of the songs he tries to sing is "MyselfYourself". Later on, one of the scene titles is actually "Myself;Yourself".
** Mashiro recommends several SF works to Louise, one of them being "New Soldier Vangeil" (the Japanese pronounciation of it closely resembles the Japanese name of Anime/NeonGenesisEvangelion).
** WordOfGod is that several of the scene titles are Shout Outs to various songs of rock bands, particularly those of TheRollingStones.
* ShrinkingViolet- Yuuri, who often gets scared when people even try to talk to her, though she's considerably much more open and cheerful around Natsuhiko and Mashiro.
* SlasherSmile: [[spoiler:Nagisa]] frequently displays this expression.
* StepfordSmiler: [[spoiler:Mashiro]], who is using her cheerful attitude to hide [[spoiler:Yuuri's death from Natsuhiko.]]
* StupidityIsTheOnlyOption: Averted- taking stupid, heroic actions will most likely result in the player [[ItsAWonderfulFailure getting killed]], while picking calm, logical options are almost always rewarded (though this trope is played straight in some cases). Kazami even lampshades this at one point.
* SugarAndIcePersonality- Kazami, though she's less "cold" than she is "professional".
* SurvivorsGuilt: [[spoiler:Watase, who felt guilty that his sister Wataru gave up her life to save his, since he felt she had much more to look forward to in life than he did.]]
* TakeAThirdOption: [[spoiler:In Root D's climax, Natsuhiko is given the choice of either giving Yuuri up to Watase, or using Senses Sympathy to erase Watase's memories again. In the True Ending, he chooses neither, and instead uses Senses Sympathy to prove that it was "Q" that started the whole chain of incidents that ruined everyone's lives (Watase's included), and so Watase throws away his allegiance to "Q".]]
* TheKillerInMe: [[spoiler:Watase falls under heavy suspicion of this towards the end of Root A, as the others claim either he killed all corpses in the facility before he lost his memories, or that he's just faking his amnesia. Depending on the ending, Watase either continues to deny or accepts the first option.]]
* ThroughTheEyesOfMadness: [[spoiler:All of Root B, where Natsuhiko is actually deluding that Yuuri is with him, when in reality, she's dead. When Natsuhiko reads Mashiro's mind and sees her memories, we see in her version of the morning, there is no Yuuri, and Natsuhiko is just talking to himself the whole time.]]
* TogetherInDeath: [[spoiler:Natsuhiko and Yuuri in Root D Bad Ending #2, Watase and Kazami in Root D Bad Ending #5.]]
* TomatoInTheMirror: [[spoiler:Watase is one of the terrorists responsible for the incident in LABO. Subverted in that while he is shocked to learn this, as soon as Natsuhiko gives him all his memories back, he shows no hesitation in returning to who he was.]]
* TookALevelInBadass: Natsuhiko. By the beginning of the game, he's just an OrdinaryHighSchoolStudent. [[spoiler:By the end of the game, he's quite possibly the most powerful Communicator in existence.]]
* TragicKeepsake: [[spoiler:Kazami's pendant was a gift that Jun and Nagisa had bought for her the day of their accident, which they had planned to give to Kazami as thanks for everything she did for them.]]
* TraumaInducedAmnesia: [[spoiler:When Natsuhiko heard of Yuuri's death nine years ago (from inhaling too much smoke when trapped in LABO), he fell into a coma for three months. When he woke up, he had completely forgotten about it, and whenever he tried to remember/someone else tried to make him remember, his mind would always repress the memory. He even started deluding of a fake Yuuri to keep his sanity.]]
* TooSoon- The game (dealing with a meltdown of a nuclear reactor) had its development halted for four months due to the 2011 Japanese earthquake, which lead to the partial meltdown of several nuclear reactors.
** [[spoiler:Which is ironic, given that it turns out that there is no nuclear reactor (and therefore no meltdown) in LABO.]]
* [[spoiler:UnreliableNarrator: The prologues of both Root A and Root B leave out key details that aren't revealed until later.]]
* UsedToBeASweetKid: [[spoiler:Nagisa used to just be an innocent child who loved her sister and her best friend Jun, but years of being forced to read hundreds of other people's memories and being put through other cruel experiments tranformed her into a psychotic, malice filled being.]]
* VitriolicBestBuds: This is essentially [[spoiler:Watase and Natsuhiko's]] relationship by the end of the game.
* [[spoiler:WeAreAsMayflies: Inverted- Communicators in general have shorter lifespans than humans (due to the gene mutations in the [=IGF2R=] gene that determines if one is a Communicator), with Level S Potential Communcators only have about 20-30 years of lifespan.]]
* WellIntentionedExtremist: [[spoiler:Watase and Ukita both have genuinely good reasons for wanting to free Yuuri and Nagisa (Watase because he wants to expose Rokumei City's wrongdoings, and Ukita because he feels bad for them), but their methods are rather extreme.]]
* WhereAreTheyNowEpilogue: [[spoiler:The Epilogue shows what the main cast's lives are like one year after the LABO incident.]]
* {{Workaholic}}- Miyoko, Natsuhiko's mother, who spends almost all her time working at LABO, which has left Natsuhiko a bit bitter towards her.
* YouAreNumberSix: [[spoiler:Yuuri, Nagisa, and Louise were referred to as Subject Y II, Subject N, and Subject Y by the LABO staff.]]
* YouGottaHaveBlueHair- Kazami (purple), Jun (green), Yuuri (lilac).
* YoungerThanTheyLook- Ukita, who, despite his grey-white hair, is only 35 years old (which surprises Watase).