Continuity mistake: When Charley and Ed are arguing in the abandoned house, the light switches on the wall next to Ed change positions repeatedly between shots even though neither of the characters ever touch them.
Continuity mistake: Ed's left hand moves back and forth from grasping Charlie's shirt collar to around his neck as the shots change from the rear of Charlie to his front.
Factual error: Jerry digs up a natural gas pipeline in the backyard and jerks it so hard that a pipe coupling in Charlie's house breaks, venting natural gas into the house for about 4 seconds. Then Jerry uses a cigarette lighter to send a flame through the pipeline, exploding Charlie's house like a fire bomb, catching virtually every room in the house on fire. In reality, it would take an hour or more for vented natural gas to accumulate sufficiently to blow up a house, for one thing. For another thing, Jerry broke the gas pipeline in the backyard in order to ignite it; so, while the broken pipeline leading to Charlie's house had no gas pressure, the pressurized side of the pipeline was still in the backyard with Jerry. Meaning, Jerry himself should have been engulfed in fire as soon as he sparked a flame.
