There is a scene in the film where we see a group of kids wearing long coats. The previous film in this series was so popular that young people in Hong Kong dressed like the lead character and the scene comments on that trend.
Lung Si (Dean Shek) is meant to be an older, retired crime boss who had previously employed Sung Tse-Ho (Lung Ti). In reality, Lung Ti is nearly 4 years older than Dean Shek.
This film was notorious for stunt mishaps. Yun-Fat Chow was almost blown up when the explosion outside the mansion door being more powerful than expected. Some of his hair was singed, and he was blasted forward. The shot in the film is his real reaction. Director Ronny Yu was the stunt double in the warehouse scene. He wrenched his back after slipping on water puddle while carrying Dean Shek. Also the stuntman for Leslie Cheung who performed the speedboat jump landed incorrectly and broke his foot.
During one of the action scenes at Ken's house you can clearly see that the sparks that are supposed to show the effects of bullets hitting a wall, are actually coming out of a pipe attached to the wall.