Despite research in mobile learning games has intensified over the last decade, there is relatively little research about how individual game mechanisms influence or change behavior. This article aims at understanding the influence of the game mechanism role-playing and investigates how it can be used to alter behavioral intention. In order to do so, we designed a mobile learning game to train Basic Life Support (BLS) and Cardiopulmonary Resuscitation (CPR). With the game we aim at improving laymen’s willingness to help in case of emergency. First, we illuminate the strand of research related to role-playing in the context of BLS and bystander CPR. Second, we describe the pedagogical framework of the mobile learning game that was designed to train BLS and introduce the game engine this development is based on. Third, we present the results from a first prototype testing, which we carried out with medical professionals as well as laymen in order to test game-play usability and interface. This article concludes by outlining the experimental setting of an upcoming study, which will use the mobile learning game to evaluate the influence of the game mechanism role-playing on the willingness to provide bystander CPR in case of emergency.