This paper introduces issues about a methodology for the design of serious games that help players/learners understand their decision-making process. First, we discuss the development of a video game system based on a role-switching mechanic where the player becomes the game leader of the experience. Then, we introduce game mechanics designed to induce a specific behavior, overconfidence, that helps to understand the players’ decision-making processes. Finally, we describe tools for measuring the players’ self-reflection regarding their judgment process.