Undertale
Undertale is a 2015 role-playing video game created by American indie developer Toby Fox. The player controls a child who has fallen into the Underground: a large, secluded region under the surface of the Earth, separated by a magical barrier. The player meets various monsters during the journey back to the surface, some of which may engage in combat. The combat system involves the player navigating through mini–bullet hell attacks by the opponent. They can opt to appease monsters in order to spare them instead of killing them. These choices affect the game, with the dialogue, characters, and story changing based on outcomes.
Outside of artwork and character designs by Temmie Chang and other guest designers, Fox developed the entirety of the game by himself, including the script and music. The game took inspiration from several sources, including the Brandish, Mario & Luigi, and Mother role-playing game series, bullet hell shooter series Touhou Project, role-playing game Moon: Remix RPG Adventure, and British comedy show Mr. Bean. Undertale was originally meant to be two hours in length and was set to be released in mid-2014, but experienced delays.
Undertale was released for OS X and Windows in September 2015. It was ported to Linux in 2016, PlayStation 4 and PlayStation Vita in 2017, the Nintendo Switch in 2018, and Xbox One in 2021. The game was acclaimed for its thematic material, combat system, musical score, originality, story, dialogue, and characters, although reaction to the art style was mixed. It has sold at least five million copies. It was nominated for multiple accolades, including game of the year from several gaming publications and conventions, and is considered one of the greatest video games ever made. A game with a parallel story, Deltarune, released episodically from 2018 before its full 2025 launch; further chapters are in development.
Gameplay
Undertale is a role-playing video game that uses a top-down perspective. In the game, the player controls a child and completes objectives in order to progress through the story. Players explore an underground world filled with towns and caves, and are required to solve numerous puzzles on their journey. The underground world is the home of monsters, many of whom challenge the player in combat; players decide whether to kill, flee from, or befriend them. Choices made by the player radically affect the plot and general progression of the game, with the player's morality acting as the cornerstone for the game's development.When players encounter enemies in either scripted events or random encounters, they enter a battle mode. During battles, players control a small heart which represents their soul, and must avoid attacks unleashed by the opposing monster similar to a bullet hell shooter. As the game progresses, new elements are introduced, such as colored obstacles, and boss battles which change the way players control the heart. Players may choose to attack the enemy, which involves timed button presses. Killing enemies will cause the player to earn EXP and gold. They can use the ACT option to check an enemy's attacking and defending attributes as well as perform various other actions, which vary depending on the enemy. If the player uses the right actions to respond to the enemy, or attacks them until they have low HP, they can then choose to spare them and end the fight without killing them. For some boss encounters to be completed peacefully, the player is required to survive until the character they are facing has finished their dialogue. The game features multiple story branches and endings depending on whether players choose to kill or spare their enemies; and as such, it is possible to clear the game without killing a single enemy.
Monsters will talk to the player during the battle, and the game will tell the players what the monster's feelings and actions are. Enemy attacks change based on how players interact with them, including the difficulty level. The game relies on a number of metafictional elements in both its gameplay and story. When players participate in a boss battle on a second playthrough, the dialogue will be altered depending on actions in previous playthroughs.
Plot
Undertale is set in the Underground, a realm where monsters were banished after war broke out with humans before the events of the game. The Underground is sealed from the surface by a magic barrier with a singular gap at Mount Ebott. At the start of the game a player-named human child falls into the Underground from Mount Ebott and encounters Flowey, a sentient flower who teaches the player the game's mechanics and lies about "LV", or "LOVE", in an attempt to kill them. The human is then rescued by Toriel, a motherly goat-like monster, who teaches them how to survive conflict in the Underground without killing. She intends to adopt the human, wanting to protect them from Asgore, the king of the Underground.The human eventually leaves Toriel to search for Asgore's castle, which contains the barrier to the surface world. They encounter several monsters, such as the skeletons Sans and Papyrus, two brothers who act as sentries for the Snowdin forest; Undyne, the head of the royal guard; Alphys, the kingdom's royal scientist; and Mettaton, a robotic television host Alphys created. Most of the monsters are fought, with the human choosing whether to kill them or to spare and possibly befriend the monster. During their travels, the human learns that many years ago, Asriel, the son of Asgore and Toriel, befriended the first human who fell into the Underground. When the child abruptly died, Asriel used the child's soul to pass through the barrier, intending to return the body to the surface. The humans living there attacked and killed Asriel, causing Asgore to declare war. In the present day, Asgore has collected six souls from fallen humans, and needs one more to destroy the barrier.
The game's ending depends on how the player handles encounters with monsters. If the player killed some but not all monsters, or did not kill any, they experience the "Neutral" ending. The human arrives at Asgore's castle and is forced to fight him. Sans stops the human before their confrontation, revealing that the human's "LOVE" and "EXP" are acronyms for "level of violence" and "execution points", respectively. Sans judges the human based on their accumulated "LOVE" and "EXP". The human then fights Asgore, but Flowey interrupts, killing Asgore, and transforming into a more powerful form by stealing the human souls. With the aid of the rebelling souls, the human defeats Flowey and can choose to either kill or spare him. The human then leaves the underground. They later receive a phone call from Sans, explaining the state of the Underground after the human's departure.
If the player kills no monsters before completing a "neutral" ending, they can reload their saved game to complete the "true pacifist" ending. Flowey is revealed to be a reincarnation of Asriel accidentally created by Alphys's experiments. During the fight with Asgore, Toriel stops the battle and is joined by the other monsters the human befriended. Flowey ambushes the group, absorbing the souls of all the humans and monsters in order to take an older Asriel's form. During the ensuing fight, the human manages to connect with the souls of their friends, and eventually defeats Asriel: He reverts to his child form, destroys the barrier, and expresses remorse for his actions before leaving, revealing the human's true name as Frisk. The human falls unconscious and is awoken to see their friends surrounding them. The monsters peacefully reintegrate with the humans, while the human has the option of accepting Toriel as their adoptive mother.
A third ending, known by fans as the "No Mercy" or "Genocide" ending, ensues if the player kills every single fightable monster. They must repeatedly trigger random encounters in each area until no more monsters remain. This route changes aspects of the game: many characters evacuate to escape the player, and those that remain have modified dialogue reflecting the impact their actions are having on the game's world. When the human reaches Asgore's castle, Sans attempts to stop them, but fails and is slain. Flowey kills Asgore in an attempt to obtain mercy, but is killed by the human. Chara, the first fallen child who befriended Asriel, then appears and erases the world. To enable further replays of the game, the player must give their soul to Chara, restoring the world and causing a permanent alteration to the true pacifist ending.
Development
Undertale was developed by Toby Fox across 32 months. Development was financed through a crowdfunding campaign on the website Kickstarter. The campaign was launched on June 25, 2013, with a goal of US$5,000; it ended on July 25, 2013, with US$51,124 raised by 2,398 people. Fox had little experience with game development; he and his three brothers often used RPG Maker 2000 to make role-playing games, though few were ever completed. Fox also worked on several EarthBound ROM hacks while in high school. Before the release of Undertale, he was best known for composing music for the webcomic Homestuck, starting in 2010. Undertale was the first full game that he wrote. The name of the game: Undertale was inspired from Fox noticing that the names of EarthBound and Homestuck were both made up of two words stuck together. Fox wanted the name of the game to be "similarly catchy". Another inspiration of the name for Undertale comes from the game: Cave Story where Fox swapped out the name "story" with "tale" due to the words meaning the same thing and Fox replacing "Cave" with "Under" in the game's name due to the game taking place underground.According to Fox, he was casually reading Wikipedia in December 2012 when he found its article for array data structures, something Fox did not have knowledge of. After reading the page, he thought about how he could use it to create a text system for an RPG. After completing it, he came up with the idea of creating a battle system. This system, which was created using the game creation system GameMaker: Studio, informed how Fox wrote the story, as both are intertwined. He wanted to develop a role-playing game that was different from the traditional design, which he often found "boring to play" despite his love for JRPGS. He set out to develop a game with "interesting characters", and that "utilizes the medium as a storytelling device ... instead of having the story and gameplay abstractions be completely separate".
Fox worked on the entire game independently, besides some of the art; he decided to do so to avoid relying on others. Temmie Chang worked as the main artist for the game, providing most of the sprites and concept art. Fox has said that the game's art style would likely remain the same if he had access to a larger team of artists. He found that "there's a psychological thread that says audiences become more attached to characters drawn simply rather than in detail", particularly benefiting from the use of visual gags within the art. Retrospectively, Fox described Undertale as "a huge katamari of things that that combined arbitrarily", adding that part of the story "was almost written improvisationally at the last minute".