Immersion is a concept that is frequently used in themed entertainment. Yet, while we all have an intuitive understanding of what immersion is, most industry members regard it as a fuzzy concept. I would like to give an overview of what the scientific literature has to say about immersion, where the concept is also being regarded as ill-defined. To tackle this conceptual unclarity, I would like to revolutionize the discussion by proposing a psychological framework to better understand immersion by drawing from the theory of play. Practical implementations will be included to make the framework useful for practitioners as well.