Revealing mistake: When the man holding the poodle leaps to his death, as his body smashes against the car, you can easily see that the poodle in his arms is just a stuffed doll, based on the way it bounces and moves.
Revealing mistake: Towards the end of the single-shot fight scene, you can see Oh Dae-Su visibly miss at least two punches by several inches. They go by quick, but they're there.
Continuity mistake: Near the end, when Oh Dae Su is fighting with Lee Woo Jin's bodyguard Mr. Han, the latter flips Dae Su repeatedly until Dae Su very swiftly jabs Han in the ear with a pair of scissors, the blades of which are pointing upward from his fist. Han flips Dae Su one more time and that's when he feels the injury. He looks down on Dae Su and spots the scissors on his hand, but this time the blades are pointing downward from his fist.Allister Cooper, 2011