This gangster-cop flick directed by Wai-keung Lau and Alan Mak is widely considered to be a breakthrough of Hong Kong's cop genre. It rejuvenated the local film market and made people excited about Hong Kong cinema again.

"Infernal Affairs" is a triumph in many ways. The rich story gives characters on both sides large room to develop and delivers surprises one after another. Film stars Tony Leung and Andy Lau give top-notch, unforgettable acting; Lau is at his very best and shines brighter than his any other films. In addition, the film's soundtrack is fresh and never fails to thrill the audience.

The smart, star-studded thriller also made a big impact on Hollywood. It inspired the American remake "The Departed," which won a best picture Oscar and a long-craving best director Oscar for master director Martin Scorsese in 2007.