As to be expected from Toby Fox, but to the point that people have said that most if not all of the soundtrack is a step up from the previous game's soundtrack. You can once again find it on Toby Fox's
Bandcamp.
General
- The new battle theme, "Rude Buster", is a sharp departure from Undertale's Battle Theme "Enemy Approaching", replacing the sweeping, triumphant-sounding, cheery song with a frantic, punchy, yet funky beat, fitting of the darker setting. It also sounds similar to "Bergentrückung" and the Game Over theme from the previous game.
- "The Chase" gives you an epic sounding sort of urgency, telling you that you need to act fast or just get outta there.
- "Darkness Falls", the Game Over theme if the player chooses to not continue, is a beautifully somber track.
- "Gallery" is the song that plays right before you fight the Chapter's Arc Villain for the first time, and it lets you know that the situation has become hairy.
- "Before the Story", which plays on the file select screen once you've beaten the game once, is a beautiful call back to the first game's main theme.
Chapter 1
- "The Legend", as Ralsei tells "The Prophecy of Delta Rune". It starts out as a simple 8-bit theme akin to Undertale's "Once Upon a Time", but then suddenly becomes more bombastic and dramatic when the legend gets to the destruction and coming of the Delta Warriors.
- "Don't Forget", a vocal song by Laura Shigihara, plays during the credits of Chapter 1, with lyrics about how no matter how dark it may seem, You Are Not Alone. At the same time, it doesn't end on the dominant chord, giving it a slightly eerie feel, given that "I'm with you in the dark" can have several interpretations, not all of them cheerful.
- "Lancer," Lancer's leitmotif, is a very catchy piece that tries to sound intimidating but ends up endearing and goofy, which perfectly complements Lancer’s characterization.
- "Field of Hopes and Dreams", the theme of the first major area, is a delightful tune that will get your feet tapping with the beats. It also features the “Don’t Forget” melody, Deltarune’s Recurring Riff.
- "Lantern", Seam's theme, is a beautiful, but melancholic waltz-like theme for the shopkeeper who's given up on everything. It's also a slowed down version of Rude Buster.
- "Checker Dance", K. Round's theme. Upbeat, energetic, and extremely goofy, it's perfect for a comedic yet dangerous enemy like him. The beginning sounds like something that would play while a predator chases its prey and toys with it for a bit before going in for the kill.
- "Scarlet Forest" is a beautiful orchestral theme and one of the best tracks from either game, even including the game's Recurring Riff.
- "Vs. Susie" turns Susie's leitmotif into a hard rock track that's overflowing with coolness and attitude, while representing Susie's heartache over Lancer's apparent betrayal. This cover gives it live instrumentation with some twists of its own to make a real headbanger.
- "Chaos King", which plays during the boss fight against the King, turns "Card Castle", which played during the preceding dungeon, into a climactic-sounding fight track reminiscent of the previous game's "Bergentrückung" in terms of sound, purpose, and epicness.
- "THE WORLD REVOLVING", the theme of Chapter 1's Superboss: Jevil, the Mad Jester. A grand, wild, bombastic tune with calliope instrumentation fitting of Jevil's clown-like nature, and swinging synth-trumpets fitting of an incredibly difficult bonus boss fight. With motifs from "Don't Forget", many consider this song to be the best of Chapter 1's Soundtrack. As an added bonus, many listeners have commented that it sounds like something out of the Mario & Luigi games.
Chapter 2
- "Faint Glow", a hauntingly mysterious rendition of "Don't Forget" that plays on the file select screen of Chapter 2. Sadly, you probably won't get to hear much of it in-game, since it gets permanently replaced by "Before the Story" once you've completed the chapter.
- "Girl Next Door", Noelle's first Leitmotif, is a very warm and relaxing wintry song that wouldn't be out of place in a Deltarune Christmas Special.
- "My Castle Town" is a gorgeously crafted piece that plays in — where else — the Castle Town, featuring a soothing yet melancholic piano waltz that helps sell the whimsical, but eerie nature of the Dark World. After the three year wait between chapters, it serves as a nice welcome back to the player.
- "A CYBER'S WORLD?", which plays in the Cyber Field area, is a wonderfully catchy and bouncy theme, which might remind you of "Fields of Hopes and Dreams". Moreover, it's the first song that you hear once you transition from Sweet's musical attack to entering the Cyber Field, giving you the impression that, after so long, Chapter 2 has officially begun.
- "Cyber Battle" is an absolutely groovy track that, much like Kris' posse and Sweet Cap'n Cakes, will make you want to get up and dance to the beat. Even better? The song just so happens to be guest arranged by Lena Raine, who many will recognize for her work on the Celeste soundtrack, which itself already had plenty of bangers.
- "Smart Race", Berdly's battle theme, is an incredibly catchy and uncharacteristically badass theme that adds a layer of menace and power for a character who, up to that point, seemed to be little more than an annoying Nerdy Bully, to the point that some have compared it to a Touhou battle theme. Fittingly for Berdly, it's also a little bit too fast and smug, giving the impression of a kid rushing to finish his test or give the correct answer in class.
- "WELCOME TO THE CITY" is a fun, bouncy, and nostalgic remix of "A CYBER'S WORLD?" that (fittingly) sounds like something from a shopping mall. This was also the first song that Toby revealed before Chapter 2's release, and it was certainly good pick. The alternative version that plays when the Weird Route requirements up to that point are met is slowed down and melancholic, with added long notes and a louder rhythm section.
- "NOW'S YOUR CHANCE TO BE A", Spamton's battle theme, is extremely catchy for a (seemingly) minor boss in Chapter 2. What really makes it amazing is the well coordinated sample of the phrase "Now's your chance to be a big shot!" that plays for half of the track, making it almost sound like a track by Hideki Naganuma or, given the '80s-style orchestra hits, Art of Noise.
- "Spamton", of which "NOW'S YOUR CHANCE TO BE A" is a remix, is a smooth yet subtly sinister track reminiscent of keygen music, befitting a shady online dealer. "Deal Gone Wrong", its Dark Reprise that plays both when Spamton NEO first appears and during the Weird Route, takes a short and slowed-down sample from this song and turns it into something else entirely that feels almost like a funeral dirge.
- "BIG SHOT", the theme of Chapter 2's superboss, Spamton NEO, takes it even further, tying it to Jevil's theme by integrating parts of "THE WORLD REVOLVING", but also "Dummy!" and "The Power of NEO" from Undertale, which is in many ways rather appropriate, which serves to highlight the height of the challenge the heroes face and Spamton's madness and longing for freedom.
- "Spamton
- "It's Pronounced "Rules"" is a proper battle theme for Roulxs Kaard after he turns heel again and attempts to stop you from reaching Queen, a significantly longer and genuinely battle-ready remix of Roulxs' theme from part 1. While still short, it's no doubt what a lot of people were expecting a lengthened battle remix of his bombastic leitmotif to sound like, and even though it's only 59 seconds long, it's still excellent.
- "Lost Girl", the second version of Noelle's Leitmotif. It's a beautifully tranquil harp-and-piano song that sounds incredibly lonely, yet still has an underlying glimmer of hope—an excellent representation of Noelle as a character.
- "Queen" is a very pompous harpsichord piece that fits the Laughably Evil personality of, well, the Queen perfectly. Since the player ends up seeing quite a lot of her throughout the chapter, it gets several remixes:
- "Pandora Palace" plays as you and your party are Storming the Castle... er, mansion. Unlike the sinister sounding "Card Castle" before it, "Pandora Palace" is absolutely banging, and it serves to motivate the player as they attempt the final stretch of the game. As a neat bonus, it sounds a bit like the Haltmann Works Company HQ theme from Kirby: Planet Robobot, which played in a similar-looking enemy base, all the while carrying a distinct Scooby-Doo chase scene feel to it to wrap the whole feel up nicely.
- "Attack of the Killer Queen" is the Boss Remix that plays when you finally fight Queen at the climax of Chapter 2. The tempo and rhythm underneath the Queen's Leitmotif are very similar to "Chaos King", showcasing both characters' affiliation with the mysterious Roaring Knight and willingness to wreck the heroes for the sake of their goals. It also contains the latter half of "Smart Race" as a reference to her control over Berdly, adding a new layer to the song.
- The final boss theme, "Knock you Down !!", a high octane theme where you combine powers with your friends and pilot a Humongous Mecha in a battle against the giant Giga Queen Robot. Not only does the whole setup scream Super Sentai, but the music itself is just celebrating you throwing back at the Queen and taking the fight to her instead, particularly if you have been pacifist this whole time. The song that leads into it, "Powers Combined," helps to hype it up.
- "Pandora Palace
- While "Until Next Time" might sound like it was glitched at first (primarily if you were expecting "Don't Forget" again, maybe with a bit of a punch to it), it plays akin to a lo-fi techno-based remix of "Don't Forget", including faint vocals of "When the light is running low, don't forget I'm with you in the dark" being heard in the track. Some fans even compare it to a Porter Robinson influenced track.
