Following the success of his thesis project "Who's that knocking at my door", Scorcese returned in 1973 with Mean Streets. Like a lot of other of Scorcese's films, Mean Streets explores the catholic guilt of the main character(Keitel) while drawing a contrast to another(DeNiro).
Keitel is near perfect in his role. In most other films, the audience would hardly consider Keitel a protagonist. He runs numbers, wacthes strippers, and does not "love" his girlfriend. However, when compared to Deniro's Johnny boy or some of the other characters in the film, one can't help but admire his altruism. In Mean Streets, Keitel plays the only role he is capable of playing well: A man stuck in two different worlds; In this case the world of clubs, dark alleys and violent street corners and the other more peaceful and disciplined world he strives for.
I don't care much for DeNiro's character, so I will not comment much on him, however it is only fitting that I reccomend some other films for Kietel fans on fans of this genre. Bad Lieutenant is the best place for any Keitel fan to start, but it is certainly not for the faint hearted. Taxi Driver also stars Keitel, but DeNiro is the main character. These films both tell the story of a man who is so fed up with the turmoil he observes every day on the streets, that he takes a road which eventually results in his own destruction.