Undertale is a 2D RPG created by an American independent developer, Toby Fox. The game describes a story of a child who has fallen into a dungeon, secluded by a magical shield. The main hero has to tear his way to the surface, meeting different monsters, capable of helping or harming him, engaging him in knotted side quests or provoking him for a battle. The fight system has a bullet hell style, whereas the player has to move among enemy balls, which can be used to suppress or subordinate the monster. In the end of every battle, the player can decide whether to kill the enemy or spare. The choices influence other characters or even the game plot.