Undertale is an indie role-playing game, created and published by Toby Fox.
The player controls a boy who has fallen down a hole into a mysterious region filled with monsters, on his quest to return to the surface.
The battle system allows the player to spare monsters and befriend bosses instead of killing them. It is possible to complete the game without killing a single enemy, which grants a unique "pacifist" ending sequence.
The game was funded via Kickstarter, with an initial goal of $5,000. The campaign raised a total of $51,124, and hit all stretch goals.
The PC version was released to critical acclaim, with a Metacritic score of 92, and Overwhelmingly Positive customer reviews on Steam.