Undertale is a well recognized name in the retro-style indie gaming scene, namely for its well-loved narrative and choice-matters dynamic. The game was almost completely solo developed by indie developer Toby Fox, including the programming, music, and narrative, though Fox was aided by Temmie Chang and other guest designers for the game art. Fun fact: The game was allegedly developed after Fox was inspired by the Wikipedia article on array data structures, and hoped to utilize them to create an RPG with a unique story and battle system. The game was released in September 2015 for OS X and Windows, Linux in 2016, Playstation 4 and Vita in 2017, Nintendo Switch in 2018, and Xbox One in 2021. Despite its older release, Undertale continues to be relevant in modern gaming culture, and to some is considered a cult classic!
The game itself is a pixelated single-player RPG where the player takes on the role of a child character that’s fallen into the “Underground”. Now separated between the game setting and Earth by a magical barrier, the player aims to reach the surface once more through traversing the fantasy world — often interacting with NPCs and engaging in combat. Undertale implements various elements that invite players to immerse themselves in the world’s narrative, particularly through continuous worldbuilding through dialogue and interaction, unique characters with rich personalities, and player agency and consequential choices.
Worldbuilding through Dialogue and Interaction
The game begins with a short cutscene providing the premise for the game lore, including a cute and appealing art style and retro-style game soundtrack. Upon this scene, the player interacts with the first NPCs — each of which provide unique insight into the game mechanics and narrative through dialogue with the player. For example, Flowey introduces the player to their basic character stats and how to mechanically move the heart within the box, which becomes important to later gameplay (Figure 1). Then, Toriel Dreemurr introduces the player to additional worldbuilding lore while serving as a guide and protector through the traversal of the ‘Underground’, teaching the player how to interact with puzzles and enemies.
Unique Characters with Rich Personalities
Each character in Undertale has a unique and rich personality, which immerses the player deeper in interaction and worldbuilding. Since characters feel distinct and possess certain dominant characteristics, the player gains a sense of familiarity and predictability with them — similar to how someone would a friend in real life. Most of these personalities are endearing in ways — namely, loving, humorous, pitiful, and others — and when they’re not they’re almost humorous to the player. For example, when the player first meets Sans, a joke is almost immediately told, indicating Sans is a lighthearted or humorous character, which significantly parallels the malicious personality of Flowey and the maternal personality of Toriel. Additionally, each character appears to have their own desires, motivations, and backstories, each of which are uniquely complex. Players slowly build relationships with these characters, and almost complete a puzzle as they get to know them. This would appear to evoke significant player empathy, as these interactions feel rich, genuine, and deep, paralleling real experiences. Players may also find themselves connecting more to particular characters, which aids in their immersion.

Player Agency and Consequential Choices
Arguably the most fundamental dynamics that encourages players to care about the world in Undertale are player agency and consequential choices. As a choice-matters game, players immediately feel a deeper connection to the world and the narrative storytelling as they’re actively taking part in shaping it. The game itself makes it clear to players that during interactions, they have a ‘choice’ with lasting and important consequences for the story. These choices are often grounded in morality, allowing players to choose between pacifying or subduing, showing mercy or killing (Figure 3). The game initially its worldbuilding telling players a war broke out between humans and monsters, and since the player depicts a human, it subsequently asks the player to take a stance on this war by providing them the opportunity to harm the monsters they encounter or choose nonviolence.
- Pacifist Ending: Occurs when players spare most (or every) monsters and results in a world with peaceful co-existence between humans and monsters.
- Neutral Ending: Occurs when players kill some monsters and spare others, which results in different variations of endings dependent on player choices (there are some Youtube videos that go through these endings and rank them that are over 40 minutes long).
- Sinister* Ending: Occurs when players kill most (or every) monsters in the game and results in a dark and eerie ending.
In addition to these three particular dynamics, Undertale features a particularly endearing artstyle and soundtrack, both of which have become well-loved by players as part of the games unique appeal through sensory experiences. The nostalgic feel of the game and its implementation of rich story building and narrative appeals significantly to emotional experiences. And lastly, the narrative provides players with a reason to stay, as they’re able to contribute to the creation of the story and continue uncovering underlying mysteries about the world and characters within it as play progresses. Undertale utilizes a series of intentional design choices, particularly with worldbuilding through interaction, unique complex characters, and consequential choices that immerse the player in the world through fantasy, narrative, and emotional appeals.
*It is important to note that the terms that refer to these ending types are not explicitly stated in the game itself and were actually coined by players. What I have referred to as the “Sinister Ending” is actually more popularly known as the “Genocide Ending” by players and netizens. However, the name for the “Genocide” ending was allegedly coined by a streamer who was making jokes in reference to the Holocaust, bringing into question the implications of its continued use to refer to this particular game ending.
Ethics Portion: Undertale as a Commentary on War and ‘Outgroups’
As a game rooted in moral decision making and agency, Undertale is intentional in its message about what is ‘right’ and ‘wrong’ — rewarding players for choosing pacifism and mercy by resulting in a feel-good ending with a positive outcome, and punishing them for choosing otherwise by resulting in an eerie and dark ending sequence. However, the depiction of war in Undertale would appear to perpetuate harmful ideas about military and war. Although Undertale, through its dynamics, appears to reward players for ‘humanizing’ the monsters and encourage empathy and fellowship, the depicting of rivals as monsters may be problematic. The game begins by introducing players to the background that two races ruled over Earth: Humans and Monsters. They also learn that a war broke out between the two races, and humans condemned monsters to live in the ‘Underground’. It is later revealed that the humans provoked the war due to fear over the monsters absorbing human souls and becoming stronger, but the player lacks this insight until the end of the game, causing them to take a stance in violence or nonviolence against a species without information about their relations with humans. Choosing to unveil this background at the end of the story feels like a very intentional design choice, causing the player to reflect on their actions given this new information, but it does call into question how players are punished based on a series of decision making relying on an incomplete premise. For example, players who view monsters as inherently more powerful or dangerous may begin the game believing the monsters initiated the war — a premise which may cause them to play differently than if they had believed otherwise. It is also important to note who in particular is playing this game, as individuals across background will have complex and unique feelings surrounding stories where one must take a stance upon a war against an ‘other’ species.
Lastly, in many games that implement war as a key component of narrative background or premises, there appears to be this distinction between ‘humans’ and ‘monsters’. Inherently, as the player themself is a human and often plays as a human character, they resonate their identity with belonging to this species, alienating the other species (in this case, monsters) as being outsiders. Depicting war as existing between ‘your species’ and ‘another species’ is a sentiment I feel can be very dangerous, particularly when player choice will influence the outcome of this war. When the designers intention is to, at least partially, cause players to question real-life applications and morality, I feel it is very important to be intentional about the way war between beings is depicted. Particularly so when appearing to be creating an ingroup vs outgroup mentality, depicting wars between humans — that the player identities with — against monsters, as the applications of this mentality to real-life scenarios may cause dangerous perceptions of dehumanization when someone identifies ethnically, culturally, or nationally with a nation or state participating in war.