Sean Gilman’s review published on Letterboxd :
About 20 minutes into the climax of the movie, after Donnie Yen has been beating the hell out of a guy (and being equally beaten in return), Donnie, for the first time in the film, takes his jacket off, as if to say "OK, now I'm really gonna get violent." He does.
By the numbers cop-triad movie. Donnie's the cop who breaks all the rules, Louis Koo is his partner, undercover among ethnically outsider criminals (Vietnamese in this case), on the eve of the Handover. The details of the criminal organization, the investigation, the legal ramifications of anything, are basically ignored, as is pretty much anything else outside of the basic narrative tissue connecting the action sequences. Yen's previous collaboration with director Wilson Yip, SPL: Sha Po Lang was a meditation on fathers and sons as much as a cops-and-gangsters story, but there's none of that here. Instead, it's Donnie leaping from one brutal fight to the next, culminating in the final, MMA-derived (lots of Muay Thai elbows and knees and wrestling holds) bout of fisticuffs.
The film opens and closes with Donnie, who has consistently brutalized suspects on- and off-camera, being asked if he'd ever assaulted an innocent person. His non-answer would be telling, but these questions seem like they come out of another movie, one where it would even be possible for Donnie Yen to be wrong about anything.