Cassette Beasts' plot is inspired by isekai, a subgenre of fantasy that revolves around a person being transported to and surviving in another world. However, the game changes normal conventions of the genre by having everyone the player meets in the game also be transported to the island of New Wirral in a similar manner. According to writer Jay Baylis, this was done to allow the team to put focus on the people who are present in the game.