Inevitable after Bullet to the Head and I'm sure more John Woo Hong Kong classics will follow. Again far superior to all of his Hollywood efforts that I've seen.
The setup is immortal: the Hong Kong police, notionally engaging in a subtle long game with the Triads, are provoked into some heroic ultraviolence. Perhaps Infernal Affairs finally killed this genre in 2002. Most of what you need to know is there on the poster: Chow Yun-Fat with a baby and a boomstick, bandaged and ridiculous.
A brief visit to a jazz club softens us up for the first course: a meeting of some sort in a bird teahouse (bring your own caged bird) that rapidly descends into a massive gunfight involving "Tequila" Chow. (You have to recognise the name actors to understand the stakes here.) Afterwards we're told that he recently broke up with fellow cop Teresa Mo which perhaps explains the bloodlust. Woo, playing a bartending ex-cop, runs the club and dispenses wisdom whenever the movie needs to take a breath. Chow later has a few great scenes with his boss Superintendent Philip Chan.
Tony Leung is introduced by an assassination in a library; librarian Hoi-Shan Lai looked on with ambiguous curiosity. Chow's investigatory superpowers lead him (17m52s) directly to the the literature aisle where he briefly mistakes a fat volume of Henry Lawson’s works as the hiding place of Leung's weapon. (But no, it was the middle volume of a Shakespeare collection that done it.) Tony is implausibly squeezeless throughout.
On the Triad side Anthony Wong is keen for a larger slice of the arms trade. This requires the elimination of the competition, Leung's boss Uncle Hoi-San Kwan, before we're properly off to the races. (Wong was memorably Leung's boss in Infernal Affairs.)
The last hour or so is totally nuts: a Terminator 2-style set piece at a large hospital. The sheer number of cops and Triad minions make it seem like a zombie flick. At one critical juncture Woo has Chow holding a blood-spattered baby in one arm and a pistol in the other — more-or-less like the poster — and arranges for that baby to be critical to Chow's survival. Leung is strangely marginalised throughout; perhaps he was told his role would have more presence.
The motorcycle stunts are often amazing. The most unrealistic thing is when someone runs out of bullets.
IMDB trivia. The guns'n'roses thing was apparently in the air. Apparently the scriptwriting proved fatal to Barry Wong.