PC-based games are currently used for training purposes throughout the military. Although increasingly popular, little research has been conducted on the design features that make these games effective training tools. This paper provides some research-based design principles that can be applied to the development of training games, with a focus on factors that influence both instructional characteristics and motivational features of PC-based games. A within-subject research design was used to identify the design characteristics that influenced the retention of information presented during the game. The aspects of the game that motivated users to continue playing were also assessed. The findings suggest that the manner in which information was presented to the user and the relevance of that information to the user's progression of the game impacted how well the information was later recalled. Graphic images and spoken text were recalled more accurately than printed text. Participants recalled procedures better than facts. Information relevant to the progression of the game was recalled better than information that was tangential to the game storyline. In addition, motivation to continue playing the game was influenced by perceived levels of challenge, realism, control, and exploration. The findings from the current research correlated with previous research in the fields of training methodology, multimedia instruction, and game development. Based on the current findings and previous research, principles for developing training games that are both instructional and motivational are presented.