This chapter treats computer game playing as an affective activity, largely guided by the audio-visual aesthetics of game content (of which, here, we concentrate on the role of sound) and the pleasure of gameplay. To understand the aesthetic impact of game sound on player experience, definitions of emotions are briefly discussed and framed in the game context. This leads to an introduction of empirical methods for assessing physiological and psychological effects of play, such as the affective impact of sonic playergame interaction. The psychological methodology presented is largely based on subjective interpretation of experience, while psychophysiological methodology is based on measurable bodily changes, such as context-dependent, physiological experience. As a means to illustrate both the potential and the difficulties inherent in such methodology we discuss the results of some experiments that investigate game sound and music effects and, finally, we close with a discussion of possible research directions based on a speculative assessment of the future of player-game interaction through affective sound.