A common feature of many digital games is that they are played in a simulated 3D environment, a game world. Simulated illumination is the lighting designed into a game world. This thesis explores the influence of simulated illumination in digital games upon the emotion and behavior of the player. It does so within the context of game aesthetics, building upon an understanding of games as having the potential to evoke an aesthetic experience that is deeply absorbing, is experienced as whole and coherent, evokes intense feelings or emotions, and engages a sense of “make believe.” A full account of how simulated illumination affects people is gained by tracing the contributions from media practice and real-space lighting, as well as taking int...