Video games are ideal media to study the relationship between human emotions and physical space, as they involve complex spatial navigation tasks while also being explicitly designed to trigger players’ emotional responses—especially in horror games. In this project, we capture emotion of players in video games, through their affect manifestations when streaming “let’s play” gameplay footage on the YouTube video platform. We extract suprise, fear and arousal signals as manifested through facial expressions, voice signals, and verbal narration of YouTube streamers while playing the horror game Outlast. We match those emotion manifestations with level design parameters, to find what design patterns lead to elevated emotions when playing a horror game.