Continuity mistake: At the final fighting scene (David Sloan vs.Tong Po), you can see that Tong Po's hair (a half shaved head with only a ponytail on it) is as fake as it can be: everytime when he moves his head a bit to rough around (sweeping his ponytail around while fighting) clearly shows that he's wearing a special kind of wig attached to his head. That 'wig' is so badly attached that it looks like he's got rimples on the back and on top of his head.
Visible crew/equipment: Towards the end, just after Tong Po releases David Sloan into the fighting arena, you can see the reflection of numerous cameras on Sloan's back.
Revealing mistake: The dead girl in the holding cell can be seen breathing.
Continuity mistake: Towards the end, while Sloan and the others are fighting, the sun changes in every shot.
Continuity mistake: After Tong Po shoots the quitters, the dead body lying inside the door changes position between shots.
