Characters of Brick: Brendan- Main Protagonist

Brendan Frye, played by Joseph Gordon Levitt, is the main protagonist of the film.With his scruffy hair, round spectacles, and hands always shoved in his pockets, Brendan gets an SOS call from his ex-girlfriend, asking him to help her. Still driven with love for her, he goes on a quest to find out information about her disappearance-- getting a couple bumps and bruises on the way.  Brendan, noted as an "adolescent Phillip Marlowe" (Gonsalves), a social outcast, doesn't fit into any of the stereotypical social cliques, and can be found eating lunch behind the schools port-a-pottys by himself. Like main protagonists in film noir, they have a flaw. Brendan has a past that haunts him, which is the past relationship he had with Emily. When Emily meets with Brendan for the last time, she asks him to please "just let me go", something that Brendan never actually answers. It is not until the final scene of the film where Brendan solves the case of her disappearance where he finally lets her go.
How is he similar/different to Phillip Marlowe?
Well, to start off, Phillip Marlowe is a prrivate detective, not a cop, who prefers to work with little or no help. He keeps to himself and is usually found alone. He is "morally upright" and never falls into the femme fatale's trap. He's quick talking, clever, and is driven to discover the truth in cases. He prefers to work alone in his cases without the aide of the police. He puts a mean tough front at first, and then as you get to know his character you realize his good intentions and strong morals.

Sound familiar? Let's break it down. Brendan is a social outcast, he prefers to be alone. Though he is solely working by himself in the film, he has a fellow peer, Brain, keeping a hidden eye out for him. He makes it clear in the film that he doesn't want any involvement of his vice principle (which can serve as a symbolism to the Law )  in the case that he's working on. He puts up a "hard-boiled" tough front, just like Marlowe, but is driven by his past love for his ex-girlfriend to find out the truth behind he disappearance (Levy).
Interesting how the two match up, isn't it?