This article examines the notion of genre in video games. The main argument is that the market-based categories of genre that have been developed in the context of video games obscure the new medium's crucial defining feature, by dividing them into categories (loosely) organized by their similarities to prior forms of mediation. The article explores the inherent tension between the conception of video games as a unified new media form, and the current fragmented genre-based approach that explicitly or implicitly concatenates video games with prior media forms. This tension reflects the current debate, within the fledgling discipline of Game Studies, between those who advocate narrative as the primary tool for understanding video games, "narratologists," and those that oppose this notion, "ludologists." In reference to this tension, the article argues that video game genres be examined in order to assess what kind of assumptions stem from the uncritical acceptance of genre as a descriptive category. Through a critical examination of the key game genres, this article will demonstrate how the clearly defined genre boundaries collapse to reveal structural similarities between the genres that exist within the current genre system, defined within the context of visual aesthetic or narrative structure. The inability of the current genre descriptions to locate and highlight these particular features suggests that to privilege the categories of the visual and narrative is a failure to understand the medium. The article concludes by suggesting that the tension between "ludology" and "narratology" can be more constructively engaged by conceptualizing video games as operating in the interplay between these two taxonomies of genre.