This thesis explores how the increase in accessibility of live broadcasting platforms for players of video games, such as Twitch.tv, affects the ways highly-skilled game players are using their gameplay to create content to be consumed by others. For players and viewers who commit to beating a game as quickly as possible, or speedrunning it, preference for this type of content leads to both groups coming together in community around their shared gameplay interests. This paper applies the polymedia theory of Madianou and Miller (2013) and the concept of polymediation (Calka, 2015) to explore how these groups experience gameplay in a mediated setting. Through ethnographic observations at a major speedrunning broadcasting event and a public chat server, and follow-up interviews and Super Mario World gameplay, three ways in which this type of gameplay content is mediated are analyzed. First, it is mediated through the deliberate, audience-focused additions of technological and gameplay-enhancing content. Second, it is mediated through a purposeful separation of casual gaming for entertainment from “serious” gameplay as a craft. Finally, it is mediated through the engagement and collaboration of an inclusive gameplay-centered community.