There were many movies made around the time this one was made with "Ji Do" (Extreme) as part of its title. They were all Cat 3 movies. This one roughly translates to "Extreme Animal Nature". Carrie Ng gets her extreme animal nature from a serum made out of (I believe) snake venoms.
Most Cat 3 movies were made for skin exposures with little or silly stories to them, But this one seems to be a regular movie that fell on the side of Cat 3 due to its contents. The story is that good, or at least on par with other Hong Kong detective movies of the time.
Carry Ng comes to close as au natural as she possibly could in this movie. If I may comment on the body style of many Hong Kong actress is that they look thinner than they really are. Especially they have nice large rear end that's only noticeable if you look directly from the back (take Chingmy Yau for instance). They look thin when viewed from the side or the front. Large butt is considered sign of fortune in Asia, so these women would be considered harbinger of good fortune to themselves and to their husbands.
Well anyways, you will get to see Carrie's naked butt in this movie, if that ever matters. She's a seriously good actor as we all know, and she plays the role of woman who has two sides to her really well in this movie. Especially the way she plays a person afflicted by the snake was superb. There are few Hong Kong luminaries that could truly be called a "star", and her performance shows that she's one of them.
So the bottom line of this movie is that it has good plot, and story to it with extremely good performance by Ng that also features her beauty the way it should be. I'm glad that they made this movie during the zenith of her career.