More often than not, sequels are a huge letdown. They're not well thought out, and their sole purpose is to try to recapture the audience dollars that the initial film brought in. Such is not the case with Infernal Affairs II.
It only takes about ten minutes to see just how well thought out this complex story is. There are a handful of details that pop up in the first few scenes that immediately reflect back to moments in the first film. These are not just simple references, but rather explanations and answers for much of the behavior of the characters in part one. Infernal Affairs II is a prequel, beginning in 1991 and ending at the Hong Kong handover in 1997, yet it does so much more than simply provide back-story on the characters. Sure, we see the early years of Ming and Yan (with Edison Chen and Shawn Yue playing the young Andy Lau and Tony Leung) but their story takes a back seat to the story of Sam and Police Inspector Wong. Eric Tsang and Anthony Wong reprise their roles, and both are even more tremendous here than they were in the first film. The opening scene, which finds the two of them having a discussion at the police station, serves not only as an interesting contrast to an equivalent scene in part one, but is reason enough to see the film.
Filmbrain was trying to think of other sequels that are prequels. Of course, there is the first third of The Godfather: Part II, which was partly an inspiration for this trilogy. However, Infernal Affairs II revives every character from the first film, and adds some additional ones that will have a tremendous impact on all of them. With almost every scene comes another startling revelation about one or more characters, and by the end of the film our impressions of nearly all of them have changed, for better or worse. (Some have changed so radically that Filmbrain needs to watch part one again before diving into the final chapter.) This is an incredible achievement, and one that could only have succeeded by carefully mapping out the trilogy beforehand.
Directors Lau and Mak have maintained much of the same feel of the first film, yet given it's 90's setting they have managed to make it look like the best Hong Kong films of that decade. (Cinematographer Wai Keung Lau worked on Chungking Express, and it shows.) Besides the obvious differences (huge clunky cell phones), it is noticeably less slick than the previous film. It's also much more focused on the drama, and action scenes are kept to a minimum. That's not to say it's any less tense, it's just that shootouts are few and far between.
Looming over everybody's story is the 1997 handover of Hong Kong, and while this film is more political than the first, its role in the film is primarily as metaphor -- many of the characters are given the chance to start anew, much like Hong Kong itself.
If you've seen Infernal Affairs, you owe it to yourself to watch the sequel. If Infernal Affairs III can maintain the dramatic intensity of parts I and II, then Hong Kong can lay claim to a trilogy that can stand up to the best of them.