Although many strong claims are made for the power of computer games to promote academic learning, the narrative content of a game may reduce the learner's tendency to reflect on its academic content. The present study examines adding a low-cost instructional feature intended to promote appropriate cognitive processing of the academic content during play. College students played a computer adventure game in which they guided a character through a bunker in search of lost artwork, building electromechanical devices to open stuck doors along the way. In Experiment 1, students who filled out worksheets about wet-cell batteries before and during the game outperformed students who played the game without worksheets on a written explanation of how wet-cell batteries work (d = 0.92), multiple-choice comprehension questions about wet-cell batteries (d = 0.67), and open-ended transfer problems about wet-cell batteries (d = 0.74). In Experiment 2, participants who completed only the in-game worksheet outperformed the control group on a written explanation of wet-cell batteries (d = 0.59) and transfer problems (d = 0.67), whereas participants who completed only the pre-game worksheet did not outperform the control group on any measure. These findings point to the learning benefits of adding instructional features suggested by cognitive theories of learning.