Endings
There are three main endings in Undertale — the Neutral Route, the True Pacifist Route, and the Genocide Route — as well as Hard Mode, an unfinished fourth ending.
This ending occurs when one of these conditions are met:
- The protagonist does not befriend all plot pivotal characters (Papyrus, Undyne, Alphys).
- The True Lab has not been explored.
- The protagonist kills any, but not every, monster.
In the Neutral Route ending, the protagonist escapes the underground alone, and Sans calls them on the phone to report how the underground is doing. Depending on the protagonist's choices, many different variations of this ending are possible, mostly differing in the dialogue Sans says.
This ending occurs when all of these conditions are met:
- A Neutral Route has been completed. (A reset is not required, only reloading the player's SAVE file afterwards.)
- No monsters were killed throughout the game. (The protagonist cannot gain any EXP, and as a result, they cannot progress past LV 1.)
- Papyrus, Undyne, and Alphys have been befriended.
- The True Lab has been explored.
The True Pacifist Route ends with the barrier being broken, and the protagonist and the monsters of the underground being able to leave. Additionally, this route features the True Pacifist ending credits.
This ending occurs only when all enemies in each area (Ruins, Snowdin, Waterfall, Hotland/CORE) are killed until no one remains. This includes all bosses.
Completing the Genocide Route leads to the destruction of the game's world. Upon re-launching the game after a completed Genocide Route, the fallen human asks the protagonist to give up their SOUL to them in exchange for the recreation of the world. This effectively acts in the same way as a True Reset from the True Pacifist Route, but it also permanently alters the endings of any later Genocide or True Pacifist endings. Neutral endings after a Genocide Route are unaffected.
This mode is activated when naming the fallen human "Frisk". It results in more difficult battles in the Ruins, some exclusive to this mode, and some usually found in the CORE. Some slight dialogue and item changes are also present. Similarly to the Undertale Demo, this mode only lasts until the end of the Ruins, where the Annoying Dog arrives to announce the end of Hard Mode.