Cec Yip is one of an elite group in HK cinema : a stunningly gorgeous woman who is also a first-class actor, and her performance teeters uncomfortably between intense and hysterical. She dominates the first half of the film, which is a semi-convential suspense/horror drama, though she is less prominent in the second half, which is mainly courtroom drama.
There's all the twists and turns you'd expect, and some perhaps you wouldn't. How involved was Kitty, as the woman who displaced Patrick's wife Brenda ? Or did she ? Just what did Patrick do and when ? Paul Chun does well in the small part of prosecutor. But the main question is - will any of the evidence, the suspicion, shake Shirley's faith in her now-husband Patrick ? She seems to have no doubts. Even when Inspector Lau takes her aside and tells her evidence not admissible in court, will it make a difference ?

Comparisons to Remains Of A Woman are inevitable, as these two films are based on the same true story. And it's hard to encapsulate the differences. Both films definitely earn Category 3, and for the same reasons (very disturbing adult themes and some need-very-strong-stomach horror scenes). Both tend towards psychodrama rather than straight out horror. Both very well acted and quite involving, if a little short on credibility. The differences are subtle yet forceful. The villain is more distant, the heroine more vulnerable and pathetic, and some of the more indirect characters have more to say.

This is at times a very unsettling film which, though gory, relies more on plot and suspense for its power. The scene near the end, where critical evidence is revealed about how Brenda Wong was killed, gave me one of the greatest scares of any film ever.
Overall : worth watching.