Continuity mistake: When Brian is giving his speech at the end, it shows two policemen. The one on the left has a brown drink and the one on the right has a yellow drink. But in the next shot, the one on the right has a yellow drink and the one on the left has a clear drink. (00:21:05)
Continuity mistake: When Brian finds Peter in the rehab centre, he has 7 beers in a pack on the bed beside him in a row of 4 and a row of 3. When the camera changes, the row of 4 which is on the outside has been reduced to 3 cans. The direction on which they are facing also changes from across the bed side to side to along the bed top to bottom. (00:16:35)
Other mistake: During the scene at the rehab clinic when Brian is jogging, Peter asks if he wants to go "mess with the pregnant teens across the lake." Brian says no because "Group therapy, two o'clock." However, the sky looks as if the sun is about to rise or just set. The time cannot be anywhere close to 2:00, neither AM nor PM.