Ordinary development, good research on today's drug-dealing, satisfactory (only) acting, a just so-so plot plus a perfunctorily didactic story, nevertheless, I still recommend this as a light Sunday afternoon amuse-bouche.
We are living in a world of mixed, confusing values. What is right? What is wrong? Lin Quin is an extremely careful businessman. He has a clean family and clean life (he doesn't even smoke, not to mention drug). He is very clear-minded to the point of having a frozen heart without much feeling for the others. He knows, very rationally, all the tricks and danger of drug and drug-dealing. He knows, super-sensibly, the wants and behaviour of the drug consumers. Trafficking drug to him is only a means of accumulating wealth regardless whether it is harmful or evil. He even makes an analogy between cigarette and drug. According to the world system and world values, he is correct: as there is a demand, I supply. As the buyers (drug users) get what they want and I get what (the money) I want, we are both happy. Isn't that the world we are living in? Nick's remark at the opening and closing of the film somehow is a futile didactic statement. "For long, I didn't understand why people take drug.... actually it's all because of emptiness (loneliness). And, which is more horrible? Loneliness or drug? I really can't tell." No philosophy class but loneliness kills more, for sure, more destructive than drugs.
What touches my heart is the ending. Nick promises to continue his duty as a special agent (undercover). When loneliness comes, he also intends to take drug but at last his salvation is brought by "innocence" (personified by Jane's little daughter) who dumps the syringe for him. Only when we come to purity and innocence, goodness and kindness can we have a way out from evil.