It's an Undertale fanfic. What did you expect? OST here.
- The intro theme, "Back to Zero", sounds quite similar to "Once Upon a Time", yet gives off the impression that something's different.
- Here we go again. Flowey’s new theme feels like a reprise of "Your Best Friend", with 16-bit instruments in contrast to the 8-bit instruments of "Your Best Friend". The melody of "Finale" is used during the second half of the song. The theme is notably more upbeat, reflecting the fact that Flowey’s friendly facade is a long-term plan this time.
- "Stay Determined!", Asgore's equivalent of "Fallen Down", is a warm, gentle yet regal-sounding reprise of “Determination”.
- The new Ruins theme gives off a sense of warmth and comfort. Rather than using the original Ruins Leitmotif (which is instead used for Undyne), this theme used Asgore’s motifs, with a bit of "Your Best Friend" thrown in, representing Flowey pushing Frisk along.
- "Ain't Afraid", Napstablook's boss theme, is a catchy, upbeat dance remix of "Ghost Fight", perfectly fitting the lighthearted performance Frisk and their new friend Blooky put on in the Ruins.
- "Regret", the theme for the first part of Asgore's fight. A much grander take on a Heartache-style song. Then there's the updated version, which incorporates "Your Best Friend".
- "A Desperate Plea + Righting Wrongs", the theme that plays during the second part of Asgore's fight, mixes together "Small Shock", Asgore's normal theme, and Frisk's leitmotifs ("Reunited" and "Stronger Monsters") for a somber, yet hopeful and uplifting song befitting the situation.
- "Your Theme", Frisk's theme, has a feeling of warmth and sincerity to it. The track was inspired by "Run away, Fugitives" from Pokémon Mystery Dungeon.
- PAPYRUS, THE VERY COOL SCIENTIST!, a fittingly goofy and sciency-sounding track for The Great Papyrus.
- heya., Sans’s theme, has the same basic melody and laidback feel as “sans.”, except played in a style reminiscent of "Nyeh Heh Heh!" from the original game, fitting the way the characters' roles have been swapped.
- Papyrus's battle theme, "THE GREAT PAPYRUS' INCREDIBLY COOL BATTLE SONG! (ALSO KNOWN AS BONETROUSLE!!!)", manages to capture both the feel of the original "Bonetrousle" while also reflecting Papyrus's focus on science. The fact it incorporates the trailer version of "Bonetrousle" is just icing on the cake.
- "Lazybones", Sans's fight theme (collab with Jimmy the Bassist and Keno), which incorporates "It's Raining Somewhere Else", "Heartache", "Bonetrousle", and even "Megalovania", which all work wonderfully in creating a serious-sounding theme that fits the dynamic of the battle it's used for whilst still feeling true to its counterpart song from the original game.
- The new Waterfall theme is an awe-inspiring reprise of the original. This track feels even more melancholic than its counterpart from the original game, due to the circumstances surrounding Waterfall in this new timeline, particularly the Waterfall Incident.
- Just an Act, a melancholy track that gives off a sense of emotional vulnerability and hopelessness. It plays when Frisk heavy-heartedly confesses to Papyrus how they hide their insecurities under a charismatic facade. It also plays during Frisk’s visit to the Waterfall Incident’s gravesite and during Interlude 2.
- Heart to Heart, a soft, comforting track that gradually gets more uplifting. It plays when Papyrus reaches out to Frisk and empathises with their insecurities, learning their name and reassuring them that they are not alone. It also plays at the end of Alphys’s fight.
- Bratty and Catty’s themes, "Alley Girls" and "Dumpster Duelling", are gloriously catchy.
- "Danger! The Killer Robot Descends!", an over-the-top rock cover of "Metal Crusher". It plays during Mettaton’s fight in Waterfall.
- "Wavering Spirit", Alphys' battle theme. "Alphys" (song) fits surprisingly well with the style of "Spear of Justice", yet the theme has a more melancholy feel to it, reflecting the poor captain's inter turmoil.
- "Scientific Justice", a mashup of "Spear of Justice", "Another Medium", and "CORE" for a regular Undyne fight. The updated version is much darker and more serious, reflecting the actual circumstances of the fight.
- The Heat is Rising! Undyne's Lava Domain!, the Hotlands theme. A frenetic tune that reflects the perilous nature of the Undyne’s puzzles. It is based off Chaos Angel - Act 1 from ''Sonic Advance 3.
- While not yet completed, the Hotlands regular battle theme is pretty catchy, taking inspiration from "Metallic Madness" from Sonic the Hedgehog CD.
- Presents in the Past. A soft, sentimental remix of "Bonetrousle" that plays during the first part of Frisk and Pap's date, when Papyrus tells Frisk how he met "Santa Claus".
- Remembering the Sunshine, the track that plays during the second part of the date, when Frisk pours their heart out to their best friend Papyrus, confessing their painful backstory and telling Papyrus just how much he means to them...
- Escalating Tension! CORE-nered at the Genesis of Determination!, the CORE theme. An intense track inspired by the final boss theme from Sonic the Hedgehog 3.
- Yes. Yes! YES!!! THE MAD MANNEQUIN GETS THEIR REVENGE!!!!, Mad Dummy's boss theme. A climactic techno remix of "Dummy!", befitting the angry ghost finally getting their revenge.
- Soul-Splitting Fury! Mad Mew Mew’s Grand Debut!, Mad Mew Mew’s boss theme, manages to sound even more frenetic and intense than its equivalent in the original game.
- Stars Collide! Rise, Mettaton SPIRAL! is a very over-the-top anime-inspired track fit for a star. Napstablook alludes to it in Part 23.Napstablook: oh, i’m working on a new song for mettaton. something fast, rockish. it’s for... something special... and top secret. but it should be cool. maybe it’ll even make him feel...Frisk: ...What is it?Napstablook: oh, nothing. don’t worry about it.
- "Say Your Prayers, Punk!", the theme that plays during the final showdown with Undyne (piloting The Determinator) at the end of the CORE. Inspired by "Battle of Providence (Phase 1)" from Bravely Second, this intense track perfectly reflects Undyne’s inner turmoil and her desperation to keep her promise, really hammering in the fact that she will stop at NOTHING to strike down the human and claim the final soul.
- "Inverted Fate", the replacement for "Undertale". A beautiful mix of "Your Best Friend", "His Theme", "Reunited", "Once Upon A Time", the beta "Undertale" motif, and others.
- Lament of the Last, the theme for The Mage/Kindness. A wistful original melody.
- "Bergkönigin + TORIEL". A beautiful "ASGORE" remix in its own right. Especially the "Your Best Friend" in there. The updated versions, "Heartbroken" and "Fallen Crown", dial the beauty and emotion Up to Eleven for a truly sorrowful and final theme.
- Whatever the hell this is. All we know is that it's a MASSIVE spoiler and that it's amazing.
- "sans' very cool song", the IF equivalent of "PAPYRUS'S COOL SONG". Papyrus is not impressed.
Unofficial tracks
- "PAPYRUS!" and "THE SONG THAT PLAYS WHEN YOU FIGHT THE GREAT PAPYRUS!!!" by Keno9988iv. Especially the latter, which keeps the Mega Man feel of "Song That Might Play When You Fight Sans".
- "One Shall Prevail" by Jamangar, for Genocide Sans. A menacing song that was actually inspired by Sean Evans's Backbone! The updated version by Doctorine is even more intense.
- "...WHY?" by Starfury, a final boss theme for Papyrus in the Genocide run. It's been remixed endless times despite its noncanon status, with possibly the greatest version being Jamangar's second take. As Dorked has been very secretive regarding the Genocide final boss, saying that she has something "interesting" in mind, it is unknown who will be fought in the Judgement Hall.
