History VideoGame / UndertaleYellow

** In Undertale, it's indicated that a long time has passed since the last human fell into the Underground before Frisk did, to the point where the majority of monsters don't recognize them. In Undertale Yellow, flashbacks and various dialogue implies Clover jumped into the Underground around a year or two before Frisk at most, with Integrity falling into the Underground a several years before ''that''.[[note]]Also, while we're not given an exact time frame, the Amalgamates are implied to be recent since Snowdrake is still a homeless teenager by the time Undertale takes place.[[/note]]
** Somewhat subverted is this one isn't really a retcon, but if one takes Toby Fox's WordOfGod statements as canon, at least one six of the humans made it to Asgore and died by his hands. In Undertale Yellow, [[spoiler:the human that fell before Clover, the Blue SOUL also known as Integrity, was killed by Axis via a heavily implied BoomHeadshot. The game goes with the interpretation that they died in Waterfall when Chujin mentioned that Axis [[HideTheEvidence hid the evidence in that area]] since that's where the Old Tutu and Ballet shoes can be found in Undertale, hidden in tall grass and behind a waterfall respectively.]] [[spoiler: If one does a flawed Pacifist route, this game goes with the narrative that Clover was the human child out of the six to reach Asgore and die by his hand.]]

* AdaptationalVillainy: In ''Undertale,'' the only description for the Old Tutu and Ballet Shoes in Waterfall was that the former is covered in dust and the latter made Frisk feel "incredibly dangerous" when putting them on, [[AmbiguouslyEvil leaving it ambiguous whether Integrity killed monsters maliciously or out of self-preservation]]. Outside of that, they help Frisk out during the Neutral and Pacifist routes like the other souls. In ''Undertale Yellow,'' [[spoiler: they come across as distinctively more morally dubious.]] [[spoiler:They almost killed Kanako and Dalv, [[WouldHurtAChild the former being a young child]], and is overall described as violent by the other characters, ultimately being killed by Axis in Waterfall (albeit unintentionally).]]

** [[spoiler:In the Genocide run specifically, Martlet artificially gains one. Before the final fight on the roof, she injects herself with Determination from Alphys' lab to give herself a boost. Although, players of Undertale would be able to guess Martlet's- and any monster's who takes Determination- grim fate by the end of the battle.]]

** In Undertale, it's indicated that a long time has passed since the last human fell into the Underground before Frisk did, to the point where the majority of monsters don't recognize them. In Undertale Yellow, flashbacks and various dialogue implies Clover jumped into the Underground around a year or two before Frisk at most, with Integrity falling into the Underground a year or two before ''that''.[[note]]Also, while we're not given an exact time frame, the Amalgamates are implied to be recent since Snowdrake is still a homeless teenager by the time Undertale takes place.[[/note]]
** If one takes Toby Fox's WordOfGod statements as canon, all six of the humans made it to Asgore and died by his hands. In Undertale Yellow, [[spoiler:the human that fell before Clover, the Blue SOUL also known as Integrity, was killed by Axis via a heavily implied BoomHeadshot. The game goes with the interpretation that they died in Waterfall when Chujin mentioned that Axis [[HideTheEvidence hid the evidence in that area]] since that's where the Old Tutu and Ballet shoes can be found in Undertale, hidden in tall grass and behind a waterfall respectively.]]

* AdaptationalVillainy: In ''Undertale,'' the only description for the Old Tutu and Ballet Shoes in Waterfall was that the former is covered in dust and the latter made Frisk feel "incredibly dangerous" when putting them on, [[AmbiguouslyEvil leaving it ambiguous whether Integrity killed monsters maliciously or out of self-preservation]]. Outside of that, they help Frisk out during the Neutral and Pacifist routes like the other souls. In ''Undertale Yellow,'' [[spoiler:they're firmly in the malicious category]]. [[spoiler:They almost killed Kanako and Dalv, [[WouldHurtAChild the former being a young child]], and is overall described as violent by the other characters, ultimately being killed by Axis in Waterfall (albeit unintentionally). Their soul continued to cause problems even after their death, getting Chujin killed when it kept refusing to fuse their souls together, and being indirectly responsible for Kanako's fate as an Amalgamate.]]

* BitchInSheepsClothing: [[spoiler:Near the end of a neutral route, Flowey betrays Clover and reveals that he's been resetting Clover's progress for a long time, having manipulated them into killing Toriel to get them to leave the Ruins, only to be exasperated when they kept getting themself killed in the rest of the Underground. As a last resort, Flowey tampered with the switch in the Ruins to force them to take a different path, leading to the events in the game. He was only pretending to be their friend in the hope that they would be able to help him get the 5 [=SOULs=] from Asgore.]]

** [[spoiler:Even if you haven't exhausted Snowdin's kill counter by the time you get to the resort, the NPC that you'd give the coffee to is gone, meaning you can't complete the ChainOfDeals to free Slurpy from the flagpole.]]

* SurprisinglyRealisticOutcome: The ending to the Genocide route when compared to the ending of the Genocide route in ''Undertale'' proper. [[spoiler:Instead of Chara showing up and overpowering them to deal LaserGuidedKarma, Clover... simply takes the five [=SOULs=] with them to the surface after killing Asgore so they can be freed. Although the game puts you through the wringer for killing monsters that aren't a threat to you, Clover ultimately goes unpunished for it since Clover was ultimately there to save the [=SOULs=] and punish the monsters for killing them in the first place.]]

** In Undertale, it's indicated that a long time has passed since the last human fell into the Underground before Frisk did, to the point where the majority of monsters don't recognize them. In Undertale Yellow, flashbacks and various dialogue implies Clover jumped into the Underground around a year or two before Frisk at most, with Integrity falling into the Underground a couple years before ''that''.[[note]]Also, while we're not given an exact time frame, the Amalgamates are implied to be recent since Snowdrake is still a homeless teenager by the time Undertale takes place.[[/note]]

** During the part where Axis chases you, [[MercyMode he slows down a bit every time you get caught by him]].