Undertale is a game that offers a lot of freedom in how players act and make decisions regarding the characters. It offers three routes with multiple endings depending on what path the player wishes to take. This can result in characters having vastly different impressions of the player going from one ending to another, and if the player crosses the moral horizon, the consequences can be quite grim.

Undertale Xbox One trailer thumb
UNDERTALE Xbox One Announce Trailer

Toby Fox's Undertale celebrates being released for the first time in this Xbox One announcement trailer filled with the RPG's si cheeky humor.

Due to Undertale’s unique fighting system, most, but not all, of those choices are made while fighting enemies. Each enemy can be killed or spared depending on the player's actions. While some of those kills are understandable as self-defense, a few portray the main character as a rather cruel and heartless person willing to backstab and take advantage of others.

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9 Being Mean to Alphys

Lowering Her Self-Esteem

Undertale Alphys Date

Alphys is a quirky yet friendly scientist the player meets in Hotland. She serves as their guide and one of the main characters for the location. While her motives are revealed to not be entirely pure, she still appears helpful most of the time and tries to strike a conversation with the player on multiple occasions.

The player can choose how to respond to her questions and queries. They can show engagement or act cold and detached, giving off the impression that they don’t care about Alphys. While it’s understandable why some would be annoyed by her constant messaging, it still takes a toll on Alphys’s low self-esteem.

8 Being Cold To Asriel

Showing No Compassion

Undertale - Asriel Grown Form And Flowey's Final Form In-Game

Asriel Dreemurr is a central character in Undertale. Starting as vile and contemptible Flowey, the player eventually learns his true nature and tragic past. Asriel is a deeply traumatized boy who was broken by his state as a flower without empathy. He is the final boss of the Pacifist Route and enters his God of Hyperdeath form.

In the end, he gives up on his rampage through a show of empathy from the player and Frisk, the game's main character. The player can choose to forgive and hug Asriel or refuse to do either of those things, which is quite cruel considering the broken state he has been in until now and will return to afterward.

7 Betray Kill Muffet

Strike At The Back

Muffet Undertale

Muffet is not a friendly opponent. She attacks the player while they’re journeying through Hotland, angry at the fact that they didn’t purchase her ridiculously expensive donut. The player can kill her, survive long enough for Muffet to spare them, or eat a donut or cider bought all the way back in the ruins.

A collage with Undertale characters that are subject to some popular theories: Sans, W.D. Gaster and Frisk from Delatarune.
7 Popular Undertale Fan Theories

Toby Fox's Undertale is intentionally vague with much of its narrative, which has allowed fans to come up with these fascinating theories.

However, a player can also choose to take one of the scenarios where Muffet spares them and then attack her instead. This would result in her dying in a single hit, as she is not expecting a surprise attack. It is a very dirty move, and using it, even on someone like Muffet, is a thoroughly evil decision the player can make.

6 Kill Weak Monsters

Squash Your Opponents

undertale fighting two monsters: froggit and whimsum

Not all enemies in this game are dangerous. While some monsters, especially those in the CORE, are hostile hired mercenaries that are dead set on killing the player, others, such as those in the Ruins, are very easy to spare and not dangerous to the player. Those are enemies such as Whimsun, Migosp, and Froggit.

The player has a significant advantage over them, even with low LV, so it seems like the player is preying on someone weaker than them. Killing even a single monster locks the player out of getting the Pacifist ending, which shows how important every enemy is and how mercy and talking can be a way out with everyone.

5 Killing Toriel

Slaughter A Grieving Mother

Toriel in Undertale

Toriel is one of the first characters the player meets at the very start of the game. She is a very compassionate monster who helps the player get through the puzzles and is very worried about their safety. This is later explained by the fact that the child reminds Toriel of her own, making her very protective towards them.

At the end of the Ruins, she tests the player and challenges them to a practice fight. The way to get out of it is to continuously spare Toriel until she gives up. However, if the player fights her or betrays her and kills her after sparing, Toriel suffers a heartbreaking demise, and the player is responsible for her death.

4 Betraying Undyne

Breaking Trust Forever

Undertale Undyne House

Undyne is no pushover; she is the captain of the royal guard and one of the most aggressive monsters in the Underground. She is always on the hunt for humans and the protagonist, leading to a climactic confrontation at the end of Waterfall. The player can kill Undyne, run away, and keep her alive.

After that, if they didn’t kill any monsters before and befriended Papyrus, they could also hang out with Undyne and befriend her. Undyne would feel incredibly broken and betrayed if they kill any enemies afterward, vowing to kill the player after the ending. It is an incredibly hurtful and heartless betrayal as the player reveals themselves as a killer.

3 Killing Papyrus

Ending A Naive Skeleton

Papyrus's fight in Undertale

Papyrus may seem dangerous at first due to his chaotic puzzles, but he is a peaceful monster who doesn’t want to hurt anyone. His only reason for hunting the player is his desire to impress Undyne and earn a place in the Royal Guard. This leads to a battle against the player, but he never kills them, only putting them in a cage.

sans undertale
Undertale Mod Adds Local and Online Co-Op to Game

Undertale Together is a mod which allows the game to be played in couch co-op, but players have several ways of using the mod to play online co-op.

The player can choose to kill Papyrus, and whether they’re on neutral or genocide, it will end up being a one-hit kill after Papyrus spares the player. This is an extremely cruel and merciless slaughter that breaks Sans’s heart and forever puts him at odds with the player. Additionally, if the player follows the Genocide route, Papyrus still maintains his belief in them.

2 Committing to Genocide

Beginning The Hunt

A fight in Undertale

The genocide route involves a lot of grinding and is almost impossible to discover naturally without prior knowledge. If the player kills all enemies in the Ruins, they get a ‘but nobody came’ message during their next encounter. This means that the player entered the Genocide route and can freely proceed.

To enter this route, the player needs to go out of their way to hunt down opponents, which makes them go beyond the level of self-defense. This makes for a very cruel decision and eventually leads to the player becoming a powerful killing machine that can annihilate the entire world and take thousands of lives.

1 Attacking Monster Kid

Trying To Murder A Defenseless Child

Undertale Monster Kid

The moment that stands out in the Genocide route is the one that triggers Undyne the Undying fight. She gets mortally wounded while defending the Monster Kid, which is the event that leads to her taking up her new and improved form. While the battle is epic and memorable, the moment leading to it is a truly evil choice.

Monster Kid has always remained friendly towards the characters, even when they noticed their roughness and how everyone who came in contact with them disappeared. They are brave enough to give them a chance while standing on the bridge, and the player is given an opportunity to stop their genocide. The only way to continue is to try to kill a defenseless kid.

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Top Critic Avg: 93 /100 Critics Rec: 97%
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Released
September 15, 2015
ESRB
E10+ for Everyone 10+: Fantasy Violence, Mild Blood, Mild Language, Simulated Gambling, Use of Tobacco
Developer(s)
Toby Fox
Publisher(s)
Toby Fox, 8-4
Engine
GameMaker
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SUBSCRIPTION
DIGITAL
Checkbox: control the expandable behavior of the extra info

Dance with a slime...pet a dog...whisper your favorite secret to a knight...or ignore all of that and rain destruction upon your foes. The choices are yours—but are you determined enough to prevail?

Killing is unnecessary: negotiate out of danger using the unique battle system. Time your attacks for extra damage, then dodge enemy attacks in a style reminiscent of top-down shooters.

Original art and soundtrack brimming with personality.
Soulful, character-rich story with an emphasis on humor.

Genre(s)
RPG
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