Continuity mistake: The first time Dave takes the liquor bottle out of his shirt, he unscrews the cap before taking a swallow. The second time, on the stage, he pulls a cork out with his teeth.
Continuity mistake: In the scene where we see school children leaving the building and are going home we see two children go over to the see saw to ride on it. Buffalo Bill is talking to a little girl just outside the doorway and when it cuts in for a closer shot of the girl, you can see in the background there are now four children on the see saw; then again when the little girl starts walking home its back to the original two children who were on the see saw earlier on.