The tram that Yiu Lung runs after changes between shots. The first shot it is numbered 2165, route 39, has only 2 doors (front and back) and no markings on the side of it.
In the next shot the tram number has changed to 2042, route 3 and has markings on the side of it. Also, while Yiu Lung is running along side of it his white pants are being splattered with mud.
In the next shot the tram number has changed again to 5156, route 39, has gained a third door in the middle and the markings on the side have gone. All of the mud splatter on Yiu Lung's pants have also disappeared.
The amount of damage (bullet holes, broken windows) to the BMW car, that Yiu Lung and Ah Mei are in while trying to break through the barricade sequence towards the end, varies between shots.
The tolling of the large bell, during the church fight sequences, doesn't match up with it's swinging motion.