Prior to shooting SPL, Wilson Yip and Donnie Yen both had the same goal of making a movie that combines mesmerising storytelling with genuine action. Wilson Yip found that the recent crop of Hong Kong movies tends to be tipped on either side of the scale; Donnie Yen shared his sentiments, believing that script and dialogues play a pivotal role to making a good action movie. "Now is time to shatter some conventions, and raise the standards of action films. However, few Hong Kong directors are capable of achieving both, and I believe Wilson Yip is one." says Donnie Yen, who having watched many of Wilson Yip films like Juliet in Love, could feel that Wilson Yip is very sensitive to character development, an element seriously lacking in action films, especially those with contemporary setting. "With a fast-paced action propelled by intense characters, even the jaded audience will find this commercial blockbuster scintillating and refreshing," adds Donnie Yen.

In fact, the depth and intricacy of characterisation are the vital elements of Sha Po Lang. The story revolves around the feuds between crimelord Master Bao (Sammo Hung), and Senior Inspectors Chen Hui (Simon Yam) and Ma Jun (Donnie Yen). As the story develops, one may discover there is no clear definition to the nature of each of the characters, Wilson Yip explains, "There is no right or wrong." In the movie, when the villain murders the witnesses, he may not feel an iota of remorse, yet on returning home, he is indeed a very wonderful man in the eyes of his family. Likewise, the police may also stoop to underhand means to accomplish their goals.

Wilson Yip further elaborates that the film title Sha Po Lang is derived from three malignant stars from Chinese astrology, and they represent the personalities of the three leading roles, "Seven Kills, Destructive General and Avaricious Wolf denote obliteration, aggressive competition, and greed respectively, but they aren't necessarily malignant stars. The alignment of the three stars under certain circumstances may lead to some unexpected, wondrous occurrence."

Apart from that, the movie also explores the intricate relations between father and son. Donnie Yen explains, "It's very enigmatic, every character possesses his own views on paternity. Sammo Hung may be a boss of the underworld who pulls no punches in committing all sorts of crimes, yet he is a committed husband, a caring father. Simon Yam succeeds his father as a policeman, while my father was a policeman who died while on duty and dissuaded me from following his footsteps on his deathbed."

Another element that sets Sha Po Lang (SPL) apart from other works in the genre is that it does not rely on special effects - except to touch up the film, to give it a more modern look and feel - and neither does it piece together bits and pieces of short takes. The actors fought with real martial arts themselves, with the decisive battles between Donnie Yen and Sammo Hung, and Donnie Yen and Wu Jing, as the two major highlights of the movie.

Donnie Yen indicates that he relishes fighting under long takes, for it's more realistic, "Nowadays, the laypeople might learn some wushu at gyms. To achieve the desired outcome, and to attract the audience, we have to raise the bar, present something the audience has never seen before. Incorporating new ideas into a movie is the challenge of every filmmaker. We experimented in filming something beyond the audience's conceivability, yet at the same time, did not make it too abstract to be understood."