Infernal Affairs is the ultimate “why didn’t I think of that” high concept: a cop goes undercover as a gangster while, simultaneously, a gangster infiltrates the police force, pretending to be a cop. These two sleeper agents live underground for years before a series of mistakes clues in all the wrong people as to what’s going on and each mole is ordered to root out the problem, which in both cases happens to be themselves. It’s the Philip K. Dick movie that Michael Mann always wanted to direct, starring Tony Leung (In the Mood for Love) as the undercover cop, and pop star Andy Lau (A Simple Life) as the over-achieving gangster who’s infiltrated the police. Chris Doyle, Wong Kar-wai’s longtime cameraman and the cinematographer on Zhang Yimou’s Hero, consulted on the visuals, and the film is saturated with toxic chromium hues that turn its elaborate set pieces into individual slices of hell.