In a conversation with BAFTA-winning composer Yoko Shimomura, composer/auteur director Toby Fox spoke on teaching himself his favorite game music on piano by ear. In many ways, the soundtrack to his indie smash hit Undertale (2015) is a sharp-eared deconstruction of iconic NES and SNES-era tunes, just as the game’s story and gameplay pick apart gaming tropes. Fox started his follow-up project, Deltarune, with Chapter 1 in 2018, proceeding to Chapter 2 (2021), and now Chapters 3+4 (2025) of the ostensibly seven-chapter whole. Thus far, Deltarune has nearly doubled the two-hour runtime of Undertale’s impressive, heart-wrenching soundtrack. As a result, it sheds the charms and callbacks of its predecessor to reveal a Toby Fox who stylistically stands on his own two feet.
Chapter 1 (“The Beginning”) of Deltarune feels the most akin to the supposedly parallel Undertale world, with tracks like “You Can Always Come Home” referencing fan-favorite “Home.” Here, Fox expands his primarily NES/SNES sound palettes to cover a slew of ‘80s, ‘90s, and ‘00s adjacent soundscapes: “Vs. Susie” is just barely legally distinct from the riff in Contra’s level 2 base; “Scarlet Forest” is like plugging a Kingdom Hearts battle theme into Final Fantasy IX’s audio engine; the chipper, skipping melody in “Schools” could easily be a town theme in a GBA Pokémon game. Songs rarely go longer than one or two minutes, but they pack significant movement within that limited time.
Aside from the sonic mementos from gaming’s past, Deltarune features plenty of incidental/atmospheric pieces as new protagonists Kris and Susie are pulled deeper into the Dark World, culminating in the breathless boss theme “Chaos King.” There is a very satisfying “there and back again” hero’s journey in the tracklist, rounded out by a series of earnest tracks (and plentiful nods to Undertale). Of the forty tracks and forty minutes in Chapter 1, there’s an armful of bangers and the most palpable sense of storytelling thus far in the whole project.
Chapter 2 (“A Cyber’s World”) focuses on digital elements and relies more heavily on repeated motifs, such as the bouncy melody of “Cyber Battle (Solo)” popping its grinning head up throughout the disc. Overall, Chapter 2 is more happy-go-lucky yet less consequential, less cinematic. Even bite-sized tracks are a compositional feast, breathlessly tearing through new melodic movements every ten seconds or so. I liked the cool urgency of “Spamton” paired with the offputting vocal samples, which continue in “NOW’S YOUR CHANCE TO BE A.” Lena Raine of Celeste and Chicory fame features on “Attack of the Killer Queen,” a pseudo-Celeste track buzzing with vitality via Sega Genesis-like synths.
Fox gives Yoko Shimomura her flowers again in the Street Fighter II coded “Knock You Down !!” That’s not to say Fox doesn’t show his own trademarks—“Faint Courage (Game Over)” is a track worth dying for and showcases the reverbed 8-bit lead-in giving way to layers of chiptune that no Famicom could’ve hoped to achieve in the ‘80s. The chapter ends with the refrain of “You Can Always Come Home,” followed by “Until Next Time,” a choppy, distorted, yet comforting remix of Chapter 1’s “Don’t Forget” featuring vocals by Laura Shigihara (whose voice you may recognize from “Zombies on Your Lawn”). Chapter 2 is strongest when it’s solidifying the world-building of the Undertale/Deltarune universe, but as a whole, it’s an amusing and often catchy listen.
The setting of Chapter 3’s (“Late Night”) goofy yet slightly ominous TV game show calls for some fun, simple, NES-styled tracks (“Adventure Board,” “Sandy Board”) and a sizable number of gag-tracks, including the very Earthbound-influenced “Dump.” Standout “Ruder Buster” speeds up Chapter 1’s “Rude Buster” with a splash of Sonic Spinball MIDI-bass and sax combo. “Welcome to the Green Room” is a much-needed, chill respite from the rather relentless tempo of the chapter’s soundtrack. “Glowing Snow” is another soft, melancholic introspection befitting its title. While it’s not my favorite track, “Big City Board” highlights one of my favorite Toby Foxisms, cranking an innocent and earnest chiptune track into a wall of 8-bit chords in its closing moments. “It’s TV Time!” is perhaps the most hyper distillation of everything Konami was doing musically with its belt-scrollers on the SNES (think TMNT IV: Turtles in Time on some, err, “Glowing Snow”). “Sword” limits itself to a strictly NES style but carries the ambition of a great credits song of that era, though there’s no sigh-of-relief return home as in Chapters 1 and 2.
Chapter 4 (“Prophecy”) starts out gently, as expected. Soon, though, sax solo-laden “Castle Funk” ups the excitement as the party returns once more into the Dark World. “ATRIUM” is one of the most simple yet effective atmospheric pieces Fox has composed, especially as an intro to what may be his greatest work yet, “Dark Sanctuary.” The opening synths whip past you as the breathy choir samples lift you up amidst soaring melodies—the motif immediately speeds up into the bass-pounding “From Now On (Battle 2)” and later in the huskier, modernized “Neverending Night.”
By Chapter 4, the scale and tonal ambition of Deltarune is beginning to take flight, trading out the cutesy retro throwbacks before they grow threadbare. Tracks like the smoldering acoustics of “Fireplace,” the swinging debauchery of “A DARK ZONE,” and the playful time signatures of “The Second Sanctuary” and “The Third Sanctuary” excite me for the musical future of Deltarune and for Toby Fox as a composer. He has long proved he can effectively ape the greats and pump out a frenetic chiptune melody. More and more, he’s pushing the boundaries of his compositions rather than simply the sound palettes of his influences.
While the quirks and wiles of the Undertale formula may be losing their sheen after several hundred tracks, This music works to polish that layer away and reveal one of gaming’s truly great composers. There’s enough evidence in this first half of the to-be-completed Deltarune soundtrack to make me readily follow Toby Fox back into the Dark World.
Chapters 1 through 4 of Deltarune are available for streaming and can be purchased in separate chapters via Toby Fox’s Bandcamp or combined (ongoing) via the Deltarune Steam page.
