Revealing mistake: During the car smuggling scene where Van Damme is fighting on the boat one of the thugs slides/falls against the side of one of the cars. If you look closely, you can see the side view mirror on the car is made of rubber.
Continuity mistake: During the scene in which Alex attacks the two henchmen looking for him on the island, we see him attack the first guy and take him out. As he goes for the second bad guy we see that the bad guy has a pistol in a holster strapped to his waist. As Alex flips this guy over the pistol and holster disappear (most noticeable when the bad guy hits the ground). It is then back in place when Alex removed the gun to shoot a third bad guy coming toward him.
Revealing mistake: After Alex has crushed Zhang's hand in the cogs on top of the crane we see that while covered in blood there is no other damage to Zhang's hand. He even manages to move it and his fingers when in fact all the bones in his hand should have been crushed and the muscles and skin torn leaving his hand in tatters and unusable.
Other mistake: During the scene in which Chad and Alex are at the harbour to blow up the drugs shipment we see Alex being shot at my numerous bad guys. He has one pistol in his hand, and pulls another from his waist band. Each pistol carries around a maximum of 15 shots per clip, however he manages to fire 43 shots without reloading.
Continuity mistake: During the docks sequence, we see Chad and Alex approach a guard sitting at a table along with many other guards. Alex selects a guard least likely to attract the attention of the others and sets down his bag. He attacks and takes out the guard in an action that brings him several steps forward and yet when he picks up his bag it is at his side.
Continuity mistake: As Chang's men storm the island we see that a few of his men are out looking for Chad and Alex. When Alex comes upon the two men looking for him we see them both facing away from Alex and turn towards him as he runs out. As he takes out the first bad guy, we then see the second one repeat the same scene of turning towards him again.
Continuity mistake: During the fight sequence on the boat between Alex and the bad guy with the spurs on his shoes, Alex grabs him by the shirt with his right hand. Then when the shot changes to where he is punching him, he is now holding his shirt with his left hand and punching with his right.
Continuity mistake: On the boat where Alex has an encounter with Griffith's female bodyguard, we see her slice his waist with her knife cutting through the t-shirt he is wearing. Later during the scene, in which Alex is climbing the crane to follow Zhang, the tear in his t-shirt has disapeared.
Factual error: While the 1960s-70s era Hong Kong vehicle licence plates were period-correct as far as number sequence (no letter prefix) and having white plates front and back, the type of plastic, retro-reflecting plates shown are from the modern era (post-1983). Cars in HK from that period had non-retro-reflecting plates, with either numbers painted on with stencils, or individually mounted plastic letters.