One of the more successful Hong Kong films of recent years is Infernal Affairs, a story of an undercover cop and a police department mole. It was remade in the U.S. as The Departed and it netted Scorcese's first oscars (among others). The symmetrical plot of Infernal Affairs is cliever and complex, but the real strength of the film is the psychological struggle of people who've been undercover for so long they're not sure who they are anymore. Confession of Pain is from the same writers and directors as Infernal Affairs. The plot doesn't feature the clever symmetry of Infernal Affairs and the psychological aspects aren't as deep, but the stakes are still high and the story is still complex and interesting.
After his girlfriend commits suicide, Detective Yau Kin Bong quits the force and becomes a private investigator. He also becomes an alcoholic. His former partner and friend Lau Ching Hei keeps tabs on him, and when someone murders Hei's father-in-law, Hei's wife hires Bong to investigate the suspicious circumstances of the murder. It sounds like a pretty standard plot, but the filmmakers manage to wring a lot of complexity out of it by employing a lot of noir story elements and maybe some of the Infernal Affairs-like symmetry. It ends up being a story of betrayal and revenge, and there are numerous surprises along the way.
The lead performances by Tony Leung and Takeshi Kaneshiro are great, and the visuals are sleeker and more cinematic than Infernal Affairs. It moves a little slowly and there are some confusing hiccups along the way (perhaps a lost in translation sorta thing), but in the end, it's a very well executed noir-like mysery/thriller. Apparently, a U.S. remake of this film is also in the works, though I'm not sure this one will go over as well... *** (out of 4 stars)