This paper discusses the concept of procedural content generation-based (PCG-based) game design as a way to create new kinds of playable experiences. We examine the different ways that PCG is currently used in games, and how that use impacts the meaning of the game and the player's experience. Finally, we discuss the design and implementation of an experimental PCG-based 2D platformer called Rathenn, which provides the player with control over the level they are playing while they explore both the physical and generative spaces of the game.