The movie Infernal Affairs was a Hong Kong film co-directed by Liu Weiqiang and Mak Siu-fai. It was released in 2002. The film tells the story of the complicated relationship between an undercover police officer and a hidden gang agent, as well as the story of them sacrificing their lives to complete the mission. The movie Infernal Affairs was widely regarded as a classic Hong Kong film, and many elements of it were later imitated. For example, the movie's narrative techniques and character creation were outstanding and deeply touched the hearts of the audience. The music, special effects, and action scenes were also very exciting, adding a lot of color to the entire movie. In addition, the movie also explored some important topics such as human nature, betrayal, and faith. These topics still have meaning in today's society, so the film is widely regarded as a work of cultural value. With all these factors, the movie Infernal Affairs became a highly respected classic film and was widely regarded as a classic of Hong Kong movies.