WARNING: This fangame is made with the assumption that you have already played Undertale, so spoilers relating to backstory in that game will be unmarked.
Undertale Yellow is an in-progress fan prequel to Undertale.
Set some time after the human-monster war, the story focuses on Clover, a human child and the source of the original game's Yellow SOUL. When several humans mysteriously start going missing while travelling to Mt. Ebott, Clover decides to jump into the Underground themself to look for them. Their adventure has both new and familiar faces.
Announced only a few months after the release of the original game, the project started on February 4, 2016 after Toby Fox allowed it to be greenlit. While the full game isn't out, a demo has been made available on Gamejolt since March of the same year.
Undertale Yellow provides examples of:
- Accidental Murder: You do this to Pops in the Genocide run. You don't know the balloon is alive until after you get a "funny" voice, causing Mood Whiplash.
- Action Commands: When attacking, an eye-like meter will appear over the menu, and a bull's-eye-like circle will run across it. Confirm the attack when the bar is near the middle, and you do more damage. Don't press anything, and you won't attack.
- Abnormal Ammo: Instead of changing weapons like Frisk, Clover keeps their gun and simply changes the ammo.
- Adult Fear: The plot is kicked off by Clover (possibly a child) jumping in Mt. Ebott. Also Toriel's reaction when the second puzzle's failure results in Clover falling through the floor.
- Always Accurate Attack: Just like the 99 percent of Undertale battles.
- Ambiguously Evil: Flowey. He's seemingly helpful, even saving your progress. However, it's not yet clear if this is during the time period he was trying to be a good guy or if he's playing you for his own goals.
- Ambiguous Gender: Subverted. Clover is a girl's name, though it isn't outright stated in the game nor hinted out in this protagonist's sprite appearance.
- Ascended Extra: In the main game, the owner of the yellow SOUL was just one of the six humans who fell into the Underground and died, with their backstory only vaguely hinted at through their virtue and the equipment they left behind.
- Bait-and-Switch: When you meet Flowey, it's similar to your first meeting Flowey in Undertale, but instead he helps you save and progress.
- Bittersweet Ending: While not in the demo without the Genocide run, it has to be, for Clover is one of the captured SOULs in Undertale, meaning they will die.
- Bloodless Carnage: Like in Undertale, monsters turn to dust when killed, so no blood is spilled.
- Bullet Hell: Enemies attack with bullets of varying shapes and patterns. Battles can become hectic, due to the more challenging nature of this game in comparison to vanilla Undertale.
- Cool Hat: Clover wears one, which is no surprise given it's the item you found of theirs in Undertale proper.
- Darker and Edgier: With a Doomed Protagonist, the game has an unintentionally depressing atmosphere.
- Dead Hat Shot: The Game Over screen shows Clover's gun and hat if left for long enough.
- Doomed by Canon: Given the situation at the start of Undertale, it is not likely that Clover will live after the adventure.
- Fallen Hero: Clover is this regardless of previous playthroughs on a Genocide run, as unlike with Frisk, whose motivations for entering the Underground are ambiguous, Clover's motivations are undoubtedly good and their virtue is Justice.
- For Great Justice: Clover, whose virtue is Justice. The opening implied they went into Mt. Ebott in search of the other missing people who disappeared there.
- Functional Magic: The monsters' attack and life force.
- HeelFace Turn: Like Undertale, you can do this: do something bad, then reset and not do the bad thing in the first place.
- He Who Fights Monsters: You in a Genocide run.
- Hope Spot: Asgore, as Undertale fans know, inadvertently created one, in declaring war on the humans after Chara's and Asriel's deaths and wanting six SOULs to cross the barrier, all the while unwilling to do the actual murder. Toriel calls him out for this and this ended their relationship.
- Justified Save Point: The game is set after Flowey gained Determination (giving him the ability to save and load) but before he became fully sociopathic. Clover, unlike Frisk, doesn't have the Determination to steal it from him, but Flowey is willing to create a save file for them, with the sparkling save points being created by Flowey so Clover can call him to save.
- Late-Arrival Spoiler: The game automatically spoils a few plot points of Undertale proper, due to being a prequel. One big one is that not only is saving and loading an In-Universe power, but Flowey is aware of it and gained it before Frisk did.
- Magical Accessory: Unlike Frisk, who changed clothing and weapons, Clover keeps their Cool Hat on at all times. Instead, they get various accessories that give buffs.
- Mental Time Travel: As in Undertale proper, this is how saving is explained. Unlike Undertale, however, Clover lacked the Determination to hijack it from Flowey (as their virtue is Justice instead), so instead Flowey does it for them.
- Personality Powers: According to Word of God, Clover's Justice has different abilities compared to Frisk's and Chara's Determination, though the demo doesn't go into many of them. One difference, however, is that Clover can't save, and thus Flowey does it for you.
- Prequel: Follows the story of the yellow SOUL that came before Frisk.
- Sdrawkcab Name: Dalv. Also a reference to Vlad the Impaler, the inspiration for Bram Stoker's Dracula.
- Shock and Awe: Dalv uses lightning for all his attacks.
- Shout-Out: Dalv's lightning attacks are highly characteristic of Dracula from early installments of the Castlevania franchise.
- The manner in which he casts his cape aside for his tracking shot is particularly reminiscent of Dracula's manner of attack in the original game..
- Dalv inverted is 'Vlad' a reference to the aforementioned Vlad the Impaler as well as Alucard, the son of Dracula (debuting in the 1940's film Son of Dracula, and whose name is simply 'Dracula' spelled backwards) and recurring Castlevania character.