Continuity mistake: When a rock breaks through the glass and hits Bob, he drops his pipe. He hops outside, leaving his pipe in the floor. When he's approaching the Sheriff, he has the pipe in his mouth again.
Continuity mistake: While Mr. Klimer is forcing Debbie into the car, he for some reason seems to have a Charlie Chaplin-esque moustache which he doesn't have in any other point in the episode.