The twelve principal keywords are: fragile, lucky, relax, energy, target, amateur, family, shadow, betrayal, grateful, blind, escalate.
Although most scenes are set in Macao, the bulk of the filming takes place in studios.
When Wong Tak-chung Jackie Chan was chastising He QiuGuo Zifeng Zhang for being the first to go onto the front line, the original line was intended to be 'They were afraid that you were unable to kick the door open.' After that, He QiuGuo kicked the door open and stormed out of the room. However, on the first take Zifeng Zhang kicked the door so hard that it was destroyed, exposing it as a prop. Consequently, the scene was rewritten to imply that her character was unable to take bullets.
Of the two male leads and five male villain co-leads, Tony Ka Fai Leung was the sole performer who did not receive martial arts training. A background in martial arts was one of the criteria used when casting the co-leads.
