Videogames already have their own space on people's lives (as well as films, music, etc). Serious games are able to provide players an interactive environment where they can have a new personal fulfillment, and try to achieve certain proposes as if they were real. First Person Shooters (FPS) represent a way of virtual reality, where the player is led to explore in a 360° virtual geography experience, in a war environment, designed to provide sensations that in the extreme and in reality could cost his life. The U.S. Department of Defense has, since the year 2002, a new tool for promotion and recruitment of civilians into the army. This is an online game in which the user is invited to experience the life of a soldier of the regular army: The America's Army game, which is considered the first combat serious game. Due to its popularity and purpose we promote a study where was analyzed the extent to which the use of the game influence the behavior of its users.