The key to understanding the film lies in Simon's oft-repeated description of the focus of his neuroscience studies in college; the connection between the eye and the brain. Campos frequently punctuates the narrative with neon, strobes and loud music. They initially serve as distractions, momentarily disorientating the audience but, as the film goes on, it becomes clear that they are an integral part of the Simon Killer's rich sensory framework, prompting the audience to question what they see and hear. As interesting as this textured technical approach is, Campos' ace card is Corbet. Having already made a name for himself in a series of edgy roles, the actor is outstanding here; capturing not only Simon's slow, disquieting descent into lunacy, but also the more juvenile aspects of the character.
While many films involuntarily give their psychopaths an intriguing aura, Corbet displays Simon's amorality with a sense of sullen entitlement; there's danger in him, but it's hidden beneath the pathetic, childishly impulsive exterior of a young American with the means to travel to Paris at the drop of a hat. Diop is equally impressive, elevating the clichéd 'tart-with-a-heart' role into something weightier. With Simon Killer, Campos has created a dark, visually arresting piece that uses its ambivalence and sordidness to pose serious questions about the limits of youthful delusions.