The thesis focuses on the video game Undertale, investigating its methods for achieving immersion and emotional involvement of the player to its world and characters. The first chapter focuses on briefly introducing the game and its unique playstyle, while explaining the main points of later chapters. The second chapter explains the notion of parasocial relationships and narrative style, and gives examples relating to the game, highlighting these relationships’ role in the player’s emotional involvement. The next chapter investigates the worldbuilding of Undertale and the different methods that can be used to successfully immerse players in its world, to make the world feel authentic and give players the chance to be part of it. The final chapter further elaborates on characters and their role in making the player feel part of the game’s world, while also making the game feel part of the player’s reality ― including some unique key elements of Undertale that break away from conventional gaming experience.