In this paper, I examine how two first-person shooter (FPS) computer games set in American high schools encode different values in relation to the same historical violence. While both commit the same transgression by producing a game based on school shootings, the different sociological relationships of the designers and players to this violent phenomenon suggests a different reading of the values encoded within each game. In this paper, I locate the representational affordances of the FPS genre according to Bernadette Flynn (2005) and Alexander Galloway’s (2006) research on FPS subjectivity, Paul Virilio’s theory of military optics (1989) and John Bale’s research into the transgressive appropriation of non-game environments (2003). Building on the paradigm of values as encoded in both game design and the social context of play (Sicart 2011) (Flanagan & Nissenbaum 2014) (Hitchens, Patrickson & Young 2014), I examine how the context of the designers and the players of my case studies reveal different implicit values in relation to the sociological factors surrounding the phenomenon of school shootings. By contrasting the values encoded within these games, I hope to offer a point of differentiation for debates concerning violence in computer games.The case studies for this paper are a student-made modification (mod) of Counter-Strike and a simulation produced by the US Department of Homeland Security using the Unreal Engine. In 2007, a student from Clements High School, Texas, was expelled for building a replica of his school as a playable mod of the first-person shooter game Counter-Strike (CS), on the grounds that this representation was inappropriate in relation to historical violence (Sinclair 2007). In 2017, the US Department of Homeland Security built a first-person shooter simulation set in a high school, which was designed to train police and first responders for mass shootings in North American schools (BBC 2017) (Wales 2018). By analysing both of these within the FPS game genre, I will establish a common language with which to examine their values in both design and play.In 2013, social psychologists Nils Böckler, Thorsten Seeger, Peter Sitzer and Wilhelm Heitmeyer edited a compendium of papers that address the causes of school shootings, focusing on the Western industrial nations where this phenomenon is most prevalent – The United States of America, Canada, Germany and Finland. Whilst a number of these papers identified media glorification of violence as a significant factor, computer games were typically positioned not as a cause or trigger for gun violence, but as part of a pattern of media consumption that can influence how adolescents imagine violent acts. More importantly, computer games were identified as emerging from a “violence-affirming setting” that influences to how these mostly young, white male shooters compensate for a perceived lack of social recognition relative to their expectations. (Sitzer, 2013, 291). This lack is contextualised within the competitive nature of society, the valorisation of masculinity in terms of fearlessness, aggressive dominance in sports, as well as the broader political acceptance of violence as a means to achieve one’s goals (Bockler et al. 2013, 43). In this paper, I show how the Clements High CS mod, made by a student modder for the consumption of his peer group is consistent with the alienation that Bockler et al suggest is endemic to the experience of contemporary American school students, and resonates with the economic alienation identified in the modding community by Tiziana Terranova (2000) and Julian Küchlich (2005). In contrast, I will argue that the EDGE Simulation, made by professional designers contracted by a US government agency for the consumption of police and first responders is more consistent with the “violence-affirming setting” identified by Bockler et al. I argue that the differential of social, economic and political power between the student modder and the government agency, and the student player versus the police/first responder player illustrates how these two FPS games encode a different set of implicit values. Put simply, I argue that the Clements High CS mod encodes the symptoms of historical violence, whereas the EDGE simulation encodes the cause.