# Deltarune

Deltarune is an episodic role-playing video game in development by Toby Fox as a follow-up to his 2015 video game Undertale. In the game, the player controls a human teenager, Kris, who is destined to save the world together with Susie, a monster, and Ralsei, a prince from the Dark World. During their quest to seal the Dark Fountains prophesied to end the world, the group makes both friends and foes. The combat system is turn-based and uses bullet hell mechanics. Similarly to Undertale, enemy encounters can be resolved peacefully or through violence.
Development of Deltarune began in 2012, three years before Fox's previous game, Undertale, was released. Though it shares some characters with Undertale, it takes place in a separate setting. It features similar gameplay to Undertale, but features an overhauled battle system with multiple party members. Its first and second chapters were released for free in October 2018 and September 2021 respectively, and the next two chapters are scheduled for a paid release in 2025. Initially, the game was released on macOS and Windows, before being ported to Nintendo Switch and PlayStation 4 in 2019. The available chapters have been largely praised by critics for their soundtrack, characters, and sense of humor.

## Gameplay

Like Undertale, Deltarune is a role-playing video game with a top-down perspective. The player directly controls a human named Kris, but selects actions for other characters during battle. Similarly to Undertale, Deltarune includes both puzzles and bullet hell sections in which the player must move a heart-shaped soul around a limited area to avoid attacks. Undertale's random encounter system has been removed; players can see the enemies in the environment before they encounter them, allowing for the possibility of avoiding or deliberately engaging them.
The game uses a turn-based combat system, where players can choose from a set of actions each turn: Fight, Act, Item, Magic, Spare, and Defend. In-game mentions of these actions are stylized in all caps. Grazing attacks, defending, and hitting an enemy increase the Tension Points (TP) gauge, which allows party members to use spells or particular acts. For example, Ralsei can pacify tired enemies with a spell. When a party member's hit points (HP) drop below zero, they are downed and will not be able to fight until revived. The HP of downed party members will regenerate slowly until it reaches 1, but other healing sources can also revive a downed party member.

## Plot

Deltarune's narrative spans seven chapters, of which two have been released, with five more being planned for a later release. Although it features some characters and elements from Undertale, it takes place in a different setting.

### Chapter 1 – The Beginning

The game begins with a voice prompting the player to create an avatar, but the "vessel" is ultimately discarded, as "no one can choose who they are in this world". Instead, the player is given control of human teenager Kris, who arrives late to school one morning. After being paired up with their delinquent monster classmate Susie for a group project, their teacher, Alphys, sends the two to get chalk from the supply closet. However, the closet pulls them into a strange realm—the Dark World—where they meet the dark prince Ralsei. He tells them that the three are heroes destined to close the geyser-like Dark Fountains that give form to the Dark Worlds to preserve the balance between light and dark. A new Dark Fountain has created a Dark World east of Ralsei's, guarded by the tyrannical King. Susie, uninterested in Ralsei's story, joins King's son Lancer in fighting Kris and Ralsei, but both are convinced to change sides and join the party.
Lancer refuses to confront his father or to see his new friends hurt, so he imprisons them in King's dungeon. Susie frees Kris and Ralsei and fights Lancer, but reconciles with him and promises not to hurt King. The three confront and battle King, who falls over, exhausted. After Ralsei heals him in pity, King incapacitates and prepares to kill the heroes. If the player has not violently subdued any prior enemies, Lancer leads the Dark World's inhabitants, Darkners, in overthrowing and imprisoning King; otherwise, Susie distracts King, allowing Ralsei to put him to sleep with a spell. After sealing the Dark Fountain, Kris wakes up in an unused classroom with Susie, revealing that Dark Worlds are ordinary rooms transformed, and returns home. That night, Kris rips out their SOUL, locks it away, and draws a knife, their eye flashing red.

### Chapter 2 – A Cyber's World

The next morning, Kris's mother, Toriel, discovers Kris has eaten a whole pie with their knife. After school, Kris and Susie return to the closet Dark World and reunite with Ralsei. He instructs Kris to bring the items from the unused classroom into the closet, restoring them to their Darkner forms, then tells Kris and Susie to work on their group project with classmates Noelle and Berdly at the library's computer lab. Arriving there, they discover that a new Dark World has been created, ruled by a computer named Queen, who recruits Berdly to her side and attempts to do the same with Noelle. Ralsei also appears in the Dark World and joins the party.
At a fork in the road, Susie runs off with Ralsei. The now alone Kris joins Noelle, helping her evade Queen. Kris encounters Spamton, an insane spambot who wants to obtain "freedom" by taking their soul. Through an optional sidequest, Kris can later help Spamton upgrade himself into the superboss Spamton NEO.
Both parties are captured by Queen, but Kris and Susie escape, convince Berdly to change sides, and reunite with Ralsei. Queen reveals that any inhabitant of the Light World can open a Dark Fountain through the use of "Determination", and that she is trying to force Noelle to do so. Queen attacks the party with a giant mech, threatening to kill them if Noelle does not obey her, but Noelle refuses. Queen realizes the error of her ways and tells Noelle to choose the world she wants. Berdly attempts to create a Dark Fountain, but Ralsei stops him, warning that opening too many Fountains will cause an apocalypse known as "The Roaring", drowning the world in darkness. Kris closes the Dark Fountain.
Kris and Susie awaken in the computer lab with Noelle and Berdly, who believe that they were just dreaming. Kris relocates Queen and the computer lab's other Darkners to Ralsei's Dark World. Susie walks Kris home and is invited in by Toriel. While in the bathroom, Kris tears out their soul again, then climbs out of a window and the player's sight. After Kris returns, having put their soul back in their body, Toriel asks Susie to spend the night. After Susie falls asleep, Toriel calls the police to report that her tires have been slashed, then goes to sleep. Kris rips out their soul again, opens the front door, turns on the TV, and creates a Dark Fountain in the living room with their knife. The screen fades to black as Kris holds up their soul, and a smile appears on the static TV screen.

#### Alternate route

If the player forces Noelle to freeze enemies with her magic, an alternate route (commonly referred to as the "Snowgrave" or "Genocide" route, and internally referred to as the "Weird" or "Side B" route) occurs. The player manipulates Noelle to freeze enemies and solve puzzles by herself and makes a deal with Spamton to acquire a ring that improves her magic at the cost of her HP. She is eventually forced to freeze Berdly solid with the "SnowGrave" spell after he confronts the duo. She then leaves Kris, shaken by her actions, and is too exhausted to participate in Queen's plans.
Ralsei informs Queen of the Roaring preemptively, avoiding her battle. Kris goes to seal the Fountain alone, but is stopped by Spamton, who upgraded himself while Queen was looking for Berdly. Fighting Spamton, Kris calls for help from Susie and Ralsei, who do not respond. The player then calls for help from Noelle, who freezes Spamton. Kris seals the fountain. In the Light World, Berdly is found unresponsive, and Noelle later questions whether the Dark World really was a dream. The route ends the same way as the normal route, with Kris opening a Dark Fountain.

## Development and release
### Chapter 1

The idea for Deltarune came to Toby Fox in a fever dream he had in 2011 in college. In the dream, he saw the ending to a video game and was determined to create it. Fox was also inspired by a collection of playing card designs posted on Tumblr by artist Kanotynes. Development of the game started in 2012 but was abandoned before Fox created the first room. Some music from the original project was recycled for Undertale, most notably the main battle theme (which became Papyrus' battle theme, "Bonetrousle") and a piece called "Joker Battle" (which was reused for the Toriel fight as "Heartache"). Various factors, such as the graphics, an overhauled combat system, and Fox's mental state, made Deltarune a more challenging game to produce than Undertale.
Temmie Chang, who previously assisted Fox with character art in Undertale, served as the main artist for Deltarune. She helped design characters, sprites, and animations. Fox came up with Susie's design after playing Phoenix Wright: Ace Attorney. He originally based her on Maya Fey, and she would act "nice and cute". However, as her design progressed, she eventually turned into more of a "thug". Fox stated that he planned to give an unnamed character a fire spell that they would not be good at using but decided against adding it in the first chapter.
Deltarune was developed by Fox in GameMaker Studio 2. The game introduces a new battle system comparable to the one used in the Final Fantasy franchise, contrasting with Undertale's combat system (which shared similarities with that of the Mother series). While some of the game's music is completely new, it also incorporates portions of the Undertale soundtrack. Unlike Undertale, Fox has stated that Deltarune is planned to have only one ending.
After previously teasing something Undertale-related a day earlier, Fox released the first chapter of Deltarune for free on October 31, 2018. Initially disguised as a "survey program", it is described as a game "intended for people who have completed Undertale". As he envisioned a larger project than Undertale, he said that he needed to form a team to release the full game, which would be sold as a single package. In November 2018, Deltarune merchandise was announced in collaboration with Fangamer, including T-shirts, a poster, plushies, pin sets, keychains, and the Deltarune, Chapter 1 soundtrack on CD and vinyl.
A Nintendo Direct was released on February 13, 2019, announcing that the first chapter of Deltarune would be released on Nintendo Switch on February 28. On February 21, 2019, the official PlayStation Twitter account announced that a PlayStation 4 version of the first chapter would also be released on February 28. The Switch and PlayStation 4 versions were developed and published by 8-4.

### Chapter 2

Development of the second chapter began in May 2020. In addition to further designing the game's story and characters, Fox spent much time experimenting with game engines other than GameMaker Studio 2. He eventually concluded that GameMaker "still felt like the best fit for the project", and using the first chapter as a base, he began working in May 2020, with Fox and Chang joined by a few other team members. Fox has stated that Chapter 2 is perhaps the game's largest, due to it having the most cutscenes and its usage of a large number of characters, among other factors. In a 2020 update, he revealed that he was considering expanding his four-person team following wrist and hand pain, which had delayed production; this led them to receive over 1000 applications.
During a livestream celebrating the 6th anniversary of Undertale in September 2021, Fox announced that the second chapter would be released for free on PC and Mac two days later, on September 17. In his blog, he said that this price point was since the COVID-19 pandemic made the world "really tough for everybody recently." The Switch and PS4 versions were updated to include Chapter 2 on September 23, in conjunction with that day's Nintendo Direct.

### Upcoming chapters

Deltarune's menu shows a total of seven chapters. Initially, the third, fourth, and fifth chapters were intended to be released as a single paid title once completed, and by 2022 work on these chapters was being undertaken simultaneously. In September 2023, the third chapter became playable from beginning to end. Due to the ongoing length of development, Fox announced the following month that the initial paid release would only include the third and fourth chapters. He recruited a producer in the beginning of 2024, and his team set an internal deadline of September 1 for the completion of Chapter 4's main content, which was met. Later that year, he announced that the next two chapters were undergoing localization and being ported to consoles, and are slated to release sometime in 2025. In a December 2024 newsletter, he reiterated the third and fourth chapters would "100% come out" in 2025, and that the fifth chapter was in production.

## Reception
### Chapter 1

The first chapter of Deltarune garnered many comparisons to Undertale. Jason Schreier of Kotaku and Dominic Tarason of Rock, Paper, Shotgun compared it favorably. Schreier praised the refinements of Undertale's elements, calling it "a refreshing return". Tarason agreed, saying that Deltarune is "a higher-budget production". Although Mitchell Parton of Nintendo World Report thought that Deltarune "doesn't significantly change up the formula", he did not have a problem with it. Nintendo Life's Mitch Vogel was less positive, being disappointed that after how "fresh" Undertale was at its release, Deltarune ended up being "'just' more of the same".
A significant amount of praise was aimed at the music, with Schreier claiming that "[t]he soundtrack should be enough of a selling point." Tarason found that the music had "a fresh new edge to it," whereas Parton described it as "emotional and solid" and expressed surprise at it being composed by one person. Adam Luhrs of RPGFan praised Fox's "clever use of motifs," feeling that they were incorporated well in Deltarune's story. GameSpot's Michael Higham pointed out similarities between Deltarune and Undertale's music, believing that they're "callbacks to remind you that these two worlds are somehow bound together." Video game music group Materia Collective released the official 40-track soundtrack, composed by Toby Fox and featuring composer-songwriter Laura Shigihara on the best-selling single "Don't Forget". Fangamer released a 1-LP vinyl record on July 11, 2019.
Tarason liked the game's pixel art, calling it "more detailed and expressive" compared to Undertale, a sentiment that Parton agreed with. Higham further elaborated that Deltarune's ability to "communicate so much with so little" is one of its greatest strengths and that "character expressions and body language provide vivid displays of personality." The gameplay was also generally well received, with Parton calling it "unique" and Vogel describing the combat as "an organic and well-implemented expansion of the original". Some criticism was given by Higham, referring to some sequences—such as the Card Castle—as "a bit barebones".
Allegra Frank of Polygon mentioned that Deltarune's sense of humor is one of its "defining features". Vogel concurred, calling the humor "witty" and the story "compelling". Higham stated that "you'll be smiling ear-to-ear from the witty writing, snappy jokes, and absurdist humor". Parton and Tarason focused more on the character designs, with Tarason praising the "fresh (and lovable) set of characters" and Parton asserting that their designs range from "undeniably adorable to nightmarishly disturbing". Vogel was critical of the way that the Dark World was implemented, opining that despite it looking slightly better than Undertale, it "hardly feels like a cohesive or living place". He also criticized the "sparsely decorated hallways with very little in the way of interesting design or presentation", ending his criticism by saying that "Deltarune is unfortunately not a very pretty game to look at." Parton also listed the game's infrequent save points as a negative in his summary.
Chapter 1's soundtrack was nominated for the Game Audio Network Guild / MAGFest People's Choice Award at the 2019 G.A.N.G. Awards.

### Chapter 2

Screen Rant rated the second chapter 4.5 out of 5, saying that "[t]he quality of the experience matches that of a full-price game, and it makes the wait for the next chapters even harder", describing it in comparison to the first chapter as "[feeling] like a game that's more confident in its direction, and more willing to let players shape the fate of its characters." Ana Diaz of Polygon described Chapter 2's world as "welcoming" despite being a "harsh challenge", praising its humor and noting that it "complicates the moral and ethical questions posed by the game's predecessor, Undertale, while adding to the story started in Chapter 1." After the release of Chapter 2, the demo (which contains Chapters 1 and 2) attracted around 100,000 concurrent players on Steam, far higher than Undertale's lifetime record.