Player response in the horror video game genre is primary to its success allowing players to experience emotional arousal through elaborate game design. This thesis aims to investigate how, specifically light mechanics, can help elicit responses in Amnesia: The DarkDescent to bring attention to the light techniques that can be used by game designers to elicit such emotional reactions. Observations, interviews, and emotional facial recognition software were used to investigate the various patterns of behavior that players had while playing Amnesia: The Dark Descent. Results showed that most participants used light attributes to benefit their emotional state and all participants used them to enhance their gameplay environment. The tools that derive from light mechanics were noticed both consciously and subconsciously. Further, each participant displayed shifts of emotion, such as surprise, fear, anger, and happiness. As well as players’ physical and in-game behavior patterns were found to be related to fear responses, in terms of events where they interacted with light attributes and were in the presence of danger. The results suggest that the usage and portrayal of light attributes are dependent on the players' perception of the valued use of light and the potential of danger. It was revealed that emotional value has a significant impact on how players perceive light mechanics. Nonetheless, the individuals were able to modulate their own emotional arousal through the attributes of light mechanics.