Revealing mistake: When the Creepy Thin Man's shooting at the Angels, Lucy Liu ducks behind a wall, and we see a bullet impact just above her head out of shot. When Thin Man runs out of bullets, Lucy peeks round the corner, and poking down from the top of the screen is what looks suspiciously like a wire from the explosive used to generate the bullet hit.
Revealing mistake: When Dylan gets shot through the window by Knox, the scene is then rewound and replayed in slow motion. The playback of the speech and video seems to be at normal speed with just the pitch lowered, although the Marvin Gaye song in the background is accurately slowed down. In the same shot when it cuts to Bullet Time, immediately after firing the gun, Knox blinks. We see his eyes close, then open while the bullet has traveled a mere 4 inches from the barrel. Assuming the bullet is travelling at over 1000 feet per second, Knox is not only quick on the trigger, but has the fastest eyes as well.