Audio problem: A soda can that is supposed to be full hits the man. When the can hits the ground you can hear that it's empty.
Audio problem: In the end when Brad is taking the dead woman's ring, the Happy Toyz truck is sitting there silently. If you look closely, you can see a gentle stream of exhaust from the pipes, meaning that the truck is idling. Yet a moment later you hear it starting up.
Answer: The Pinball Machine overloaded at speed.