In the driving scene with Ricky Hui, when the Datsun 1200 reverses, the film is flipped around so we see a mirror image.
The horse-racing scene at the end has film around the wrong way: when the number 7 horse is shot, one notices its number is reversed.
The reflection on a bus driving through shows the crew members lined up, this is during the scene when Michael Hui had just gotten demoted and is taking his anger out on the car.