Revealing mistake: When Egg Shen helps the others escape by using a crossbow-and-winch device, he fires the bolt into a stone. When the bolt digs in, the stone shudders slightly (since its made of wood or plastic, and no fixed part of the floor).
Revealing mistake: During the fight between the two rival Chinese gangs, several of the men wearing black are thrown to the ground in separate shots at differing times. However, each time they land, the asphalt surface beneath them shakes visibly.
Revealing mistake: When Lightning makes his appearance in the street fight scene, at the point where his 'lightning rod' impacts, we can see a badly covered explosive charge and ignition cable on the asphalt.