Undertale

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.

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 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.

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 24, 2013, with a goal of US$5,000; it ended on July 24, 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 EarthBound ROM hacks while in high school, including the EarthBound Halloween Hack, released in 2008. 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 title Undertale was inspired from Fox's observation that EarthBound and Homestuck were both made up of two words stuck together.

Undertale received "universal acclaim" from critics, according to review aggregator website Metacritic. There, it is the third-highest rated Windows game released in 2015, and among the top 50 of all time. It was temporarily the highest-rated PC game of all time on Metacritic after release. On the review aggregator OpenCritic the game received "mighty" approval, being recommended by 97% of critics.

GameSpot's Tyler Hicks declared it "one of the most progressive and innovative RPGs to come in a long time", and IGN's Kallie Plagge called it "a masterfully crafted experience". The game has been included in various best-of lists, being ranked 20th in IGN's "The Top 100 Video Games of All Time" list in 2021 and 34th in Dexerto's "These are the 100 best games of all time" list in 2025. Undertale has been described as a spiritual successor of EarthBound.

Undertale quickly developed a cult following. About a year after release, Fox commented that he was surprised by how popular the game had become and though appreciative of the attention, he found it stressful. Fox said: "It wouldn't surprise me if I never made a game as successful again. That's fine with me though".

Ana Diaz of NPR stated that Undertale "shaped the entertainment tastes of an entire generation", and that it "took on a new life through memes". Reid Young, CEO of Fangamer, said that the game became "an absolutely dominating force". The character Sans has been well received by players, being the subject of many fan works. Professional wrestler Kenny Omega has expressed his love of Undertale, dressing as Sans for the October 30, 2019, episode of All Elite Wrestling: Dynamite.