This study investigates players’ sense of control over a game, referred to as the sense of agency (SoA). While prior research has addressed the importance of control in game interactions, understanding the factors that constitute players’ SoA remains limited. Using a mixed methods approach, we conducted interviews (n = 18) and surveys (n = 654) to gain qualitative and quantitative insights into this unique perceptual phenomenon. Multidimensional scaling analysis revealed a two-dimensional space comprising five clusters that shape players’ SoA. We then developed and tested a 12-item Game Sense of Agency questionnaire which, through exploratory and confirmatory factor analysis, measures four factors: Multisensory Presentation, Feedback Reasoning, Virtual Realism and Control Smoothness. This research identifies the multifaceted nature of players’ SoA and offers practical suggestions for how it could be measured. The outcomes contribute an empirically-driven framework for understanding and evaluating the factors that influence players’ SoA in games.