Wong says his name is "Sammo Hung" when asked by police. Sammo Kam-Bo Hung is a real-life martial artist and filmmaker.
Fans of the film in America wondered why the opening music was different. The answer is because producer shortened the film for its US release and made some music choices too. The extended cut features David Williams original score.
The Japanese Mafia at the beginning are all played by members of fight coordinator Koichi Sakamoto's Alpha Stunts team.
The directors cut features the actual character motivation for Toby Wong, his girlfriend, which was cut completely from the HBO cut. Producer/distributors felt that wasn't needed info.