Games are a popular form of digital entertainment and one elusive question is how complex visual designs affect the player experience. We address one aspect of this topic in terms of similarity of visual features, explored both as an organizing principle in Gestalt psychology and as a theory in visual attention. To address this issue, we developed a 3D railed shooter game with adjustable visual features of size, speed, and density of targets and non-targets. Based on these features we evaluate 105 player’s performance in 4 visual conditions. In addition, we employ a cognitive workload assessment as a means to understand the perceived demands on players. Results show effects of expertise on performance and cognitive workload, per visual condition. Our methods and implications on game design are discussed.