What makes video games unique as an audiovisual medium is not just that they are interactive, but that this interactivity is rule bound and goal oriented. This means that player experience, including experience of the music, is somehow shaped or structured by these characteristics. Because of its emphasis on action in perception, James Gibson's ecological approach to psychology—particularly his concept of affordances—is well suited to theorise the role of music in player experience. In a game, players perceive the environment and gameplay situations in terms of the goal-oriented actions they afford. Nondiegetic music, not tied to any place in the digital game world, can play a unique role in the structuring of these affordances. Through a series of case studies, I will show that music creates and structures situations both in the game environment (such as the appearance of enemies in Unreal) and beyond the game environment (such as the death of an avatar and the restart of a level in Super Mario Bros.).