The economic and technical advantages of modern video games engender significant interest in game-based approaches to training. However, very little research examines whether game-based approaches provide additional benefit over traditional training approaches. Most empirical research concerning training games primarily focuses on the motivating aspect of games (e.g., Corbeil, 1999; Garris et al., 2002). While this research enhances our understanding of how to apply gaming principles to training applications to retain trainee interest, it provides little understanding of which specific gaming attributes (e.g., feature control, challenge, immersion) influence the acquisition of specific knowledge and skills. Our work addresses this gap in research by: (1) developing a theoretical matrix of hypothesized relationships between gaming attributes and training outcomes, and (2) experimentally testing these hypotheses in a field study with Marine Corps trainees in the Infantry Operations Chief Course at the School of Infantry-East (SOI-East). This paper describes the methods, measures, and results of our experiments with 52 Marine Corps trainees at SOI-East investigating the impact of feature control on three training outcomes: (1) declarative knowledge, (2) motivation, and (3) application. One group of 26 participants received training that allowed greater influence over the game world (the higher-feature control condition), while a second group of 26 participants received training that allowed less influence over the game world (the lower-feature control condition). Results indicate that while there were no significant main effects of feature control on any of the three training outcomes, several interesting interactions were detected. Generally, these interactions indicated that participants with past exposure to the training material benefited from a game that allowed for higher-feature control. These interactions point to the necessity of understanding the experience level of training participants and incorporating this information into the design of a training game in order to maximize training effectiveness.