Continuity mistake: In George's memorial service, the extras are totally different in the shots from George's point of view to the shots from the back of the room. Look for the woman with brunette hair and orange overalls - she's there in the forward shots but missing in the reverses. The chairs, tables, props, costumes and character placements are all completely discontinuous. (00:12:15)
Continuity mistake: When Roseanne & Jackie talk about Arnie, they act like they haven't known him long. Jackie even states, "I don't know him." Yet, in episode "Why Jackie Becomes a Trucker," Jackie sleeps with Arnie. Roseanne says all the girls made a pact in high school that none of them would ever sleep with him.
Continuity mistake: When Miss White is writing Mrs. Heimer on the chalk board, the camera shows Kevin/the class, when the camera comes back to her, she has a different sweater, hairstyle, and her name is written in a different spot. I'm not sure if this is some kind of flash to when everyone comes back to school after summer, or an error.
Continuity mistake: "The Feverman": Before putting the chain around his neck, the doctor removes both his detachable collar and his black string tie. A few shots later, not only is the collar back, but he's now wearing a red ascot-style tie. Both collar and tie vanish again one shot later. (00:17:05)
Continuity mistake: During the car chase scene, the car passes a petrol station and heads straight towards a bus. Then the next shot shows the car on a clear piece of road where the bus and petrol station have disappeared, but in the next shot the car swerves into the petrol station seen before. The car was going straight, without turning onto any side roads.