This chapter presents state-of-the-art methods that tap the potential of psychophysics for the purpose of understanding game players' behavior. Studying gaze behavior in gaming environments has recently gained momentum as it affords a better understanding of gamers' visual attention. However, while knowing where users are attending in a computer game would be useful at a basic level, it does not provide insight into what users are interested in, or why. An answer to these questions can be tremendously useful to game designers, enabling them to improve gameplay, selectively increase visual fidelity, and optimize the distribution of computing resources. Furthermore, this could be useful in verifying game mechanics, improving game AI and smart positioning of advertisements within games, all being applications widely desirable across the games industry. Techniques are outlined to collect gaze data, and map fixation points back to semantic objects in a gaming environment, enabling a deeper understanding of how players interact with games.