Dialogue is central to many gameplay experiences, yet it remains widely unexplored and understudied. In this dissertation, we present our findings from a series of studies we conducted on dialogue systems in games. Our results point to deeper insights not only on dialogue system design, but also on deeper issues regarding how players experience games. Furthermore, we also design a survey instrument that can be used to evaluate user satisfaction in dialogue systems in games, and propose a set of quantitative metrics that can be used to evaluate player behavior. The result is a more formal and complete approach to evaluating this complicated design space.