At the beginning of the opening scene where Dennis is mulling over his future, there is a complete weather change (cloudy to very sunny) between shots because the two parts of the scene were shot at different times, complete with change in the background noise as the scene switches angle.
When Dennis and Neville are in the hospital checking up on Oz, Dennis has a bloody, bruised lip and a bruised cheekbone due to being involved in the bar fight. In the following scene back at their local bar his face looks back to normal, and even more so the following morning.