I have to see a lot of films. A lot of films. And watching The Departed made something clear to me: Most of those films are really shabbily put together. Departed, the latest crime drama from Martin Scorcese, is so expertly edited and shot, with such unerringly apt sound design and pacing, as to be completely engrossing for its 2 1/2 hours. I wanted Departed to go on forever, in a sharp contrast to other films. Leonardo DiCaprio plays good cop Billy Costigan, who goes undercover to get mob boss Frank Costello (Jack Nicholson). Meanwhile, bad cop Colin Sullivan (Matt Damon) rises through the ranks of the police force while acting as Costellos mole. There are so many interweaving threads of betrayal that youll think youre watching a German opera as staged by the current Iraqi government. Damon and DiCaprio are both excellent (Damon a bit more so), but the supporting cast is even better. Alec Baldwin is hilarious as Captain Ellerby, the jovial and yet explosively violent head of the organized-crime detail. Best of all is Mark Wahlberg as the potty-mouthed psychopath who assists the undercover agents. Departed is based on the Chinese hit Infernal Affairs, but its 100 percent American and 100 percent Scorcese. So what if he reaches a little too far and leaves a few logical loopholes in the plot? The tension and progression of the story are so good.