Familiar Affairs

The only film genre more formulaic than romantic comedies is Hong Kong action. Every time out it's the honorable cops versus the craven triads [or honorable triads and craven cops]. At some point we are introduced to one or more soulless, doting, ineffectual female characters who exist only as testaments to the hero's startling animal magnetism. There are always double and triple crosses ending in bloody showdowns. In Hong Kong action, bullets are drawn to foreheads like East Asian Mafiosi to the heroin trade.
There's often a mystery to unravel or a game of cat and mouse. Those films lacking in mystery generally compensate with a revenge plot and absurd amounts of blood--gushing out of foreheads split in two with precise gunplay.
For better and for worse, Infernal Affairs [Hong Kong action titles also generally sound like soft core porn] finds a way to incorporate each and every on of these things into a single film.
You've got your cops, who hunt your gangs who push your drugs. You have no less than two dumb female love interests, a testament to the stunning virility of both our hero and his nemesis [differently heroic in his own right]. You have your dumb former love interest, a testament to our hero's devotion to his work. I counted one double, one quadruple and one quintuple-cross, leaving everybody any of the main characters ever cared about dead. Lots of bullets find their way through lots of foreheads.
Infernal Affairs' central conceit, further, has been done countless times, but is developed well enough to be exciting. See, instead of having a triad mole in the Police Department or a cop deep undercover within the triad, Infernal Affairs does both.
Since Hong Kong action conventions have no qualms with presenting honorable criminals, Infernal Affairs allows itself to offer dueling heros. Both are so incredibly good at what they do that each man quickly realizes the existence of the other. Both are so dependable and honorable that their respective bosses [who they are deceiving remember] quickly puts each man in charge of sniffing out the other. So each man is aiding the establishment he has infiltrated while simultaneously seeking to undermine it. Sound tough to follow? It is. Probably about as hard to follow as this review.
The plot is so convoluted that I'm sure I missed the significance of half the stuff that flashed onscreen. The nods, the tapping fingers, the obsessive use of morse code. But rather than alienate the viewer, Infernal Affairs becomes incredibly compelling, because this confusion seems to mimic the confusion the characters themselves--who have had to essentially kill their real identities--must feel, constantly serving two masters.
All of this makes Infernal Affairs one of the best and most faithfully executed Hong Kong thrillers I've seen, taking convention to such a dizzying extreme that it somehow becomes fresh again.
Then finally, when one man emerges triumphant over the other, the ending is bittersweet. Both of these individuals had been treading the path of redemption, only to find those paths intersecting in the deadliest possible way. Also bittersweet is the denouement, in which those moronic female characters are trotted back out to weep and gnash their teeth lest we forget that this fallen hero was also some kind of super-virile God-man.
The last note strikes sour, but that's the fundamental tension of a story that borrows this heavily from the genre that inspired it. A step in either direction is the difference between being a masterpiece or a complete failure.
Infernal Affairs is rated R but has very little actual violence and no profanity or sex. On several occasions, though, Szechwan noodles are flung disrespectfully.