Undertale is a role-playing game created by Toby Fox. 8-4 developed the Switch version, published it digitally, and released physical copies of the title in Japan. Fangamer released physical copies of the title in other territories. The game was later succeeded by Deltarune.
In Undertale, you take control of a human named Frisk on a 2-D plain. You travel through the various environments of The Underground, on a quest to leave and go back the your home on the surface. As you go on, there are many puzzles you must solve to progress. On the way, you will run into many fights and meet characters. Though, it is unique in the fact that instead of killing all of the enemies, you can talk to them and spare them. Of course, you can choose the option to kill all of the monsters. The different actions you do will lead to a different ending for the game. In the fights, on your turn, you can fight, act, use an item, or run away. With the fight option, a bar will slide across the screen and if you land it in the middle, it will do maximum damage. With the acting option, you can start a conversation with the monster, and try to become friends with it, and it will stop fighting you. With the item option, you can consume food items you have collected and gain back the health you have lost during the battle. On the enemy's turn, they will try to attack you in a box and you move your heart around to dodge them. At the end of each of the five main areas in the game, there are boss fights, which are against the main characters and are harder than most of the random battles.
Long ago, two races ruled over the Earth: Humans and Monsters. One day, a war broke out between the two races and after a long series of battle, the humans were victorious. The greatest of their magicians confined the monsters to the Underground with a magic barrier. However, this barrier is not a perfect barrier.
Many years after the war, in 201X, a human child climbs Mount Ebott for their own mysterious reason. It is said that those who climb the mountain never return. The child discovers an enormous hole in the mountain and falls in. After that, the story begins.
The protagonist starts off their adventure in the Ruins and soon meets Flowey, a sentient flower who attempts to kill the protagonist for his own amusement. He is thwarted by a motherly monster named Toriel, who teaches the child how to solve puzzles and resolve conflicts in the Underground. After a boss fight with her, she allows the child to exit the Ruins.
Next they enter Snowdin and immediatley meet the two skeleton brothers: the lazy comedic Sans, and the energetic and bold Papyrus. Papyrus is intent on capturing the protagonist, and constantly tries to stump the human with puzzles but always fails. Finally, when the player reaches Snowdin town, Papyrus confronts the human himself and fights them, but gives up. Then the player goes to hang out at Papyrus and Sans's house but ends when Papyrus decides that the protagonist cares too much about him for their own good, and sends them back on their way.
After that, the protagonist enters Waterfall, where they are hunted by the fierce Undyne. she ambushes the player multiple times throughout Waterfall, but the player always escapes. Finally at the exit, Undyne fights the protagonist, but when she chases the protagonist into Hotland, she faints from the heat. But then the player revives her with water and goes to Undyne's house. At first she is mad that the player for coming but after some prompting from Papyrus, she becomes friends with the player.
Then, the player moves on to Hotland. There, you find out the royal scientist, Alphys has been monitoring the player throughout their journey in the underground, and that she wants to help the protagonist. But before anything else happens, Mettaton, Alphys's robot celebrity, comes to host a quiz show of death, but soon leaves. As the player travels through Hotland, they keep on running into Mettaton's performances and Alphys keeps helping them get away. Finally, the player traverses through the power station of the Underground called the CORE. At the end of it, Mettaton is waiting for them. Mettaton tells them that he was never actually trying to hurt the protagonist, and that the whole thing was just Alphys trying to be a part of the player's quest. But then, he says that his viewers are expecting a fight, and that he will deliver one. Then Mettaton runs out of battery and Alphys reveals that to leave the Underground, the player must kill Asgore, the king of the Underground.
Finally, the player reaches New Home, and learns the story of Chara, the first human to fall Underground. The royal family took them in, but she grew terminally ill and the prince, Asriel, tried to help her, but they both died in the process. Then the player meets King Asgore, who is just as reluctant to fight as the protagonist is. Then, just as Asgore was about to spare the player, Flowey kills him. Flowey then absorbs the fallen human souls and becomes a horrifying monster. but then, the human souls retaliate against him and he almost dies but is mystified when the player doesn't kill him after all he'd done, and runs away.
The player finds themself back before the Asgore fight, and upon going back to Snowdin Undyne asks them to deliver a note to Alphys. When you do so, Alphys reads it, and it turns out it was a love note. Alphys thinks it is from you, so she ends up going on a date with you. You go to the garbage dump, but are found by Undyne. Alphys confesses how she feels then goes back to her lab. When you go there, there is a note saying to go into the elevator. Upon entering it, the elevator malfunctions and plummets down.
When it stops the player finds themself in a dark underground lab. The protagonist gets attacked by creepy amalgamations of monsters but spares them. In the lab the player finds out that Alphys tried to reanimate dead monsters but it failed and they became the amalgamates.
When you go back into the elevator, it takes you straight back to New Home and when you are about to fight Asgore again, all the friends you made come to stop the fight, but Flowey comes too and uses all the monster souls to transform into his former form, Asriel. Asriel fights the player for a while, but then uses his full power to become a big winged monster and almost kills the protagonist. But suddenly, the souls of your friends resonate from within Asriel and you can save them from Asriel's control. Then Asriel realizes what he has done and uses all the souls to break the barrier. Then you go to the surface and the game ends as you and your friends look out upon the sunset.
- Frisk: Frisk is the game's main protagonist. He is a human child who fell into the Underground realm. Frisk wears a blue sweater that has a single purple stripe, black pants, and brown shoes. His hair is brown.
- Queen Toriel Dreemurr: Toriel Dreemurr is the retired monster queen and a motherly figure who lives in the ruins. Toriel and her husband Asgore had divorced after he decided to kill humans who fell into the Underground. She resembles a goat, just like the other Dreemurrs do.
- Napstablook: Napstablook is a downbeat ghost who lives in the garbage dump by the Waterfall. He means well, but sometimes makes mistakes. His appearance is your typical bedsheet ghost that has black circles for eyes.
- The Royal Guards: These characters are the royal guards for the subterranean Underground. They have canine features, like Cornerians do.
- Papyrus and Sans: These characters are two characters that hail from Snowdin. Though they cannot be more different, they love each other. Papyrus is comical, but he takes his duties seriously. Sans is lazy, and he likes to make bad puns with his companions, often annoying Papyrus.
- Captain Undyne: Undyne is the tomboyish captain of the Underground's guard force. Her appearance is a piscine, blue skinned humanoid with yellow eyes and red eyebrows and hair. She wears a black tank top, grey-blue jeans, and brown shoes. Undyne lives in the Waterfall area.
- Doctor Alphys: Alphys is the insecure royal scientist for the subterranean Underground realm. Due to a mishap in her bid to prove that monsters could handle the substance called Determination, Alphys has become somewhat of a liar; however, she means well. Alphys is reptilian with yellow skin. She has oval-lensed glasses and tends to wear a white lab coat. She and Mettaton live in hotland.
- Mettaton: Mettaton is the star in the subterranean Underground realm. He was originally created to kill humans, but his true intentions are just to provide fun for the audience. Mettaton has two forms. His normal form is a box-like mechanical creature with a screen for a face. His second form has a humanoid build and is called Mettaton EX. Mettaton and Alphys live in Hotland.
- King Asgore Dreemurr: Asgore Dreemurr roles the Underground. Though he is called a terrible being by his subjects, beneath that scary exterior is a sorrowful entity. Asgore wishes that his son, Asriel, would come back to him.
- Flowey the Flower: Flowey is the main antagonist of the game. He is the first character who meets the protagonist and becomes the final boss of the Neutral Route. His name is a pun on "Flower". His goal is to rid the subterranean Underground of the monsters. Trapped within him is Asriel Dreemurr, the lost Monster prince.
- Prince Asriel Dreemurr: Asriel Dreemurr is the lost Monster prince. He is the son of Queen Toriel and King Asgore. Just like his parents do, Asriel basically resembles a humanoid goat. Asriel and his family can master fire magic. Frisk saves him during the final boss battle of the Pacifist Route.
- Chara: Chara is the first human who falls into the Underground. Her name comes from "Character". She had a vendetta against humans, but when they met, she and prince Asriel became close friends. She became terminally ill after she feasted on some buttercups, and he buried her in a field of golden flowers out of due respect for her. The humans thought her death was his fault and damaged his body terminally. Asriel just barely made it back home before death caught him.
- Minor Characters:
- Snowdrake: A comedian from Snowdin.
- Fuku Fire: This fire elemental comes from Hotland. Her appearance is a green humanoid flame creature. She has a feminine school uniform.
- Shyren: A singer coming from Waterfall.
- Grillby: Making his home in Snowdin, this humanoid fire elemental runs a bar that Sans and Papyrus frequent. He has an orange colour.
Undertale received "universal acclaim" reviews from critics according to Metacritic with a current Metascore of 93/100.