Hard Boiled was John Woo's last Hong Kong film before his transition to Hollywood. After making films that glamorized gangsters (and receiving criticism for doing so), Woo wanted to make a Dirty Harry styled film to glamorize the police. After the death of screenwriter Barry Wong, the film's screenplay underwent constant changes during filming. New characters such as Mad Dog and Mr. Woo were introduced, while the original plotline of a baby poisoning psychopath was cut.
The film was released in Hong Kong in 1992 to generally positive audience reception, but it was not as commercially successful as Woo's previous action films, such as A Better Tomorrow and The Killer. Reception from western critics was much more positive; many critics and film scholars have come to proclaim its action scenes as among the best ever filmed. In 2007, a video game sequel titled Stranglehold was released, which is in the process of being made into a film.
In a tea house in Hong Kong, Officer "Tequila" Yuen (Chow Yun-fat) and his partner Benny (Bowie Lam), attempt to arrest a group of gun smugglers while they are making a deal. After an ambush from another gang member, a fierce gun battle breaks out. The gangsters are defeated but several police officers are badly wounded and Benny is killed. Angered by the death of his partner, Tequila decides to kill the gangster who ambushed them rather than arrest him. This angers his boss, Officer Superintendent Pang (Philip Chan), who wanted the gangster alive to testify. Tequila is subsequently ordered off the case for his misdemeanor.
Elsewhere, a high-ranking assassin, Alan (Tony Leung Chiu-wai), works for Triad boss "Uncle" Hoi (Kwan Hoi-Shan). Alan murders a fellow member of Hoi's gang, who had been working for Johnny Wong's (Anthony Wong) rival syndicate. Wong is impressed by Alan's skill and attempts to recruit him. Alan reluctantly turns against Hoi when Wong conducts a raid on Hoi's arsenal at a warehouse. At the warehouse, Wong's men kill Hoi's workers and destroy his stock. When Hoi arrives, Wong demands Alan kill Hoi, which he does, along with the rest of Hoi's men. Just then, smoke grenades explode and Tequila attacks. Alan covers Wong's escape as Tequila battles and kills most of the gangsters. In the end, Tequila finds himself confronting Alan face to face in the smoke, with guns to each other's heads. Tequila tries to shoot Alan, but finds he is out of ammo. Although he has a chance to kill Tequila, Alan slowly lowers his gun and walks away.
At the police station, Pang confirms that Alan is actually an undercover cop. Tequila tracks Alan down to his sailboat to try to make sense of the situation, but the two are ambushed by the remnants of Hoi's gang. Tequila and Alan manage to kill their attackers just before Wong arrives, which allows Alan to keep his cover. Wong realizes that one of his gangsters named Foxy (Tung Wei), is an informant for the police. Foxy is beaten at the docks by Wong's henchman Mad Dog (Philip Kwok) in front of Alan and Wong. Alan then shoots Foxy in the chest, although he secretly placed a cigarette lighter in Foxy's breast pocket earlier to prevent the shot from being fatal. Foxy finds Tequila at a jazz bar and informs him that Wong's armory is in the nearby Maple Group Hospital. As Tequila takes Foxy to the hospital, Wong finds out that Foxy is alive and sends Alan to kill Foxy, as well as sending Mad Dog separately to cover Alan. At the hospital, Alan confronts Tequila, demanding to know the whereabouts of Wong's arsenal. While Alan and Tequila are distracted, Foxy is killed by Mad Dog.