Game-based technologies are being increasingly leveraged by the military for training purposes. However, despite their perceived contribution, games are rarely empirically evaluated for their training effectiveness nor used to their full potential. Instead games are often implemented as practice environments alone, lacking instructional capabilities that are known to lead to more effective training (Clark, Yates, Early, & Moulton, 2007). In an effort to integrate evidence-based instructional design into serious games, effectively “bringing the classroom into training games,â€� the U.S. Army Research Institute collaborated with Soar Technology to develop a training game for course-of-action analysis (COAA) based on the Guided Experiential Learning (GEL) Model (Clark et al., 2010). Course of Action Analysis (“Wargamingâ€�) involves step-by-step human simulation and evaluation of a course of action. The game-based instruction (GBI) COAA prototype includes part/whole task practice, field-based problems, demonstrations, and guided practice. These methods are prescribed by GEL, which is based on Merrill's principles of instruction (Merrill, 2006). To explore the effectiveness of this approach, Soldiers were run through a study to compare the use of the GBI COAA prototype to a control that approximates how games are typically used in simulation centers (i.e., upfront instruction, practice without guided feedback, AAR/post-training feedback). Assessments included usability, attitudes toward technology, and training effectiveness/efficiency (e.g., number of errors). The goal of this evaluation was to determine whether the method used in the COAA tool is more effective and efficient when compared to current training practices. Findings support the use of embedded instruction in games; a significant decrease in the number of errors was found for Soldiers exposed to game play that featured the GEL model of instruction compared to Soldiers who had traditional training. These results will help guide future development of game-based instruction environments and provides support for the continuing use of games in training.