A great script and an energetic direction for a movie that catched me and kept me holding my breath all the way to the end. A well-constructed story with dialogues that mesure words and silences printing them in an amazing cinematography. Especially if you watch it after "The Departed", you'll understand that a movie can be strong and powerful without swearing every 15 seconds. I mean, "The Departed" is a good movie, Martin Scorsese is a master in telling crime stories, but comparing to "Infernal Affairs", it may look a little redundant of explicit sentences and with an unnecessary love triangle. Because in this film the suspense is all in the story itself and in the eyes of the lead actors, Tony Leung and Andy Lau: cool but nervous, trying to smile while they're conscious to be trapped in their own lives. And this work so accurate and unexcessive makes me think that "Infernal Affairs" has something special. It's like a machine that works perfectly with its gears and makes no more noise than is required.