Shakespearean?

I recently got around to renting The Departed , Martin Scorsese's oscar-winning film, and was impressed. Many go out of their way to put down this movie just because of the violence or the use of the 'f word'. Both seem to fit in the culture that is displayed here. Jack Nicholson's character (forgive me - I have a terrible memory for the character names, so I'll use actor names) says something to the boy he's training to be an insider (cop) for him, something like: "You can be a cop or a criminal. Is there any difference?" That's the main idea of the entire movie there. Is there really any difference? I was struck by the tragic ending and couldn't help but think of how the continual battle, the struggle to be insiders (Matt Damon vs. Leo DiCaprio) seemed to be so like a Shakespeare tragedy. I don't know how else to describe it except to say I felt the same way after seeing any of Shakespeare's plays, such as a Hamlet or, perhaps this movie better reflects: Macbeth. Some of the reviews talk about how long the movie was, but, I must admit, I was so caught up in the story of how Matt Damon was leaking info to Jack Nicholson while Leo DiCaprio was an undercover cop leaking info to the police from inside Jack's own organization - that I was surprised by the abruptness of the ending. However, in reading some reviews for Quentin Tarantino's Reservoir Dogs, I recognized the kind of violence: realistic. In reality, people live their lives, can be quite happy and BANG! violence intrudes brutally on their reality, shattering the moment. This is a movie to meditate on and think about. This is real film making at its best!