I have the Blu-ray of this one, and its on my short list since Derek Elley's review gives it 8/10, and it has Lunmei Kwai from Secret (2007).

Turned out to have a similar feel to director Dante Lam's previous movie "Fire of Conscience." Lunmei Kwai unfortunately doesn't have many action scenes. Perhaps she'll be used more in the upcoming Flying Swords of Dragon Gate.

Acting is good, and the film has its moments but ultimately just feels like a bunch of scenes pasted together. Good for an action fix but not much more. Starts off seeming like a fresh perspective on stool pigeons and how coolly and methodically they're exploited by the police but degenerates into forced drama and brutality. Characters seldom seem more than caricatures. 7/10

(Extras are just the usual fluff pieces where interviewer questions are cut out because it would be readily apparent that none of them are interesting, show any depth of knowledge, or are follow-up questions that challenge or joke about any of the fluff answers. It seems the crew are just told "Come up with something interesting to say about the movie, but make sure it doesn't reflect badly on anyone. Ramble on for about 10 minutes or so in a tone that makes even the most trivial and superficial statements sound like they're the product of careful and deep thought or that you're so impressed by other members of the crew that you're at a loss for words, and then we'll cut back and forth between different interviews frequently at random points so that viewers don't catch on to this and buy into the illusion that its a carefully crafted and incisive documentary." One of the extras is just a collection of footage from a cameraman who walks around filming stuff on set with no one paying attention to him and with little editing and no commentary whatsoever or even subtitles of what's being said by the crew.)