City on Fire (1987)

Chow Yun-fat plays Ko Chow, an undercover cop in a violent Hong Kong setting. He's tired of the work and wants to retire, but his superior, inspector Lau (Sun Yueh), wants one last job from him: infiltrate and help bring down a gang of jewellery thieves, one of whom killed a fellow cop.
Ko is, it must be said, a bit of an ass-hole who's difficult to sympathise with, despite much of the running time given over to characterisation. But he gets a little less unlikable as the story progresses.
The closing act is fantastic — it also happens to be the part that QT ripped off for Reservoir Dogs (1992) — but overall the film is too uneven for my tastes.

2½ bleeding heads out of 5