In the fight with the man in white, while they are in the bathroom, the holes they make in the wall appear and disappear between shots, most noticeable during the missing head-butt.
The same Land Rover is seen again despite being destroyed in an earlier scene. The G274 HDS number plate reveals this.
When Danny sits in the car with Bart and the other companions he pulls the steering wheel and they flip over. While they are flipping over you can see a plate on the bottom of the car (possibly for the stunt), but in the next scene you see the car on its back missing the plate.
During the fight with the bald stranger in the bathroom, the dents in the walls made from punching turn into holes.
When Jet Li kicks the man in white before the end of their fight the man is pushed back and hits a statue of a man. When Jet Li kicks again and breaks the statue it's of a woman instead.
Sam takes the plaster off Danny's arm which reveals an old looking scar not a fresh one as would be expected.
During the car crash one of the parked car's windshield explodes way before the Land Rover flies next to it.
When Bart's car is hit by a truck, the car is empty.
When Bart is being beaten by thugs near the beginning of the film, you can see the padding on his stuntman's back.
The white Jaguar featured in the film displays the registration number SJ03NEN. This would indicate a vehicle registered in the UK between March and September 2003, but the model is clearly one from the mid-1980s. DVLA rules in the UK forbid an older car from carrying an age-related plate which makes it look newer than it is, so it would not be possible for this vehicle to legally display this plate.
Set in Glasgow, Scotland. However not a single character in the film has a Scottish accent.
The truck used in the assassination is an American Mack truck, not the kind of truck used in Glasgow.
Completely set in Glasgow but in an early scene Bart (Bob Hoskins) is obviously in London.
Despite all the shooting, no sign of any police.