Revealing mistake: After the bounty hunter, who changes three times throughout the movie, changes into the Reverend, he is in front of someone else who is a stand-in for the real Reverend but is obviously not.
Factual error: The movie they're watching in the theater, "The Fly", is shown backwards. The first scene they see should have happened after the last scene they see.
Continuity mistake: Watch Gwenda's headrest after she leaves the station in her car. It disappears between shots.
Revealing mistake: A sign's wooden support gets shot at the beginning, but you can see where the pre-prepared weak point is in the support before it gets "shot."
Continuity mistake: At the end of the movie, Spence is seen with Claudia in a western movie. He walks through the swinging bar doors with a cigar in his mouth. He takes a few steps forward and the size of the cigar has nearly doubled.
Continuity mistake: During their escape the three protagonists have to wade through a canal. A few moments later their clothes are dry again. (01:02:15)
Continuity mistake: Woody Harrelson is just demoted from starting quarterback. He mentions to Goldie Hawn that he makes a great slot back. The next scene is of a slot back making a great run, only the slot back is black. He gets tackled and when he gets up you see a very white Woody with the ball.
Continuity mistake: When Roger babysits Robert, the neighbour's son, he begins to cry, so Roger sits with him and watches TV. All of a sudden the tears on the childs face miraculously dry up between cuts.
Revealing mistake: When Lazarus and Klepper's vehicle goes through the wooden crates and flips over, you can see the wooden ramp used to launch the car.
Visible crew/equipment: When the Overlord is busy destroying the Diner, when he starts destroying stuff on the counter, you can see the small rods pop up that flip the saucers and glasses into the air. You can also see the compressed air they used, to aid with the effect.
Visible crew/equipment: When Kazihiro turns off the T.V. while the Twisted Sister music video is on, you can see a crew member reflection in the television.
Continuity mistake: About half way through the video when Casey Meadows and Battle Whitherspoon are finished making love in the mountain cabin Casey is laying on Battle's left side. The next morning when they wake up Casey is on Battle's right side.
Factual error: In an early scene, the high school science teacher produces a schematic diagram of the two nuclear bomb designs created by the Manhattan Project. He says, "Here are two designs based on plutonium." Actually, only the Fat Man bomb uses plutonium. The other, the Little Boy design, uses uranium.
Continuity mistake: Ray throws Audrey into a swimming pool when he discovers that she may be sneaking out on him. She is wearing a cap, shirt, shorts, socks and sneakers and is holding a bag. In the next couple of shots, she swims away and she is barefoot.
Continuity mistake: When the pool hustler, Jason Alexander, lights his cigarette, the match goes out before it touches the cigarette yet he still takes a drag as if it were lit.
Continuity mistake: When Max has the accident with the bus, it is only a minor fender-bender. In a later scene, his car is shown in a junk yard with much more damage to it than what was originally done.
Audio problem: When Chris and Cynthia are hiding in the little shed from the zombies, there was a scene where a zombie grabs Cynthia and pulls her outside the shed. As she is being pulled out she reaches out to Chris and screams "Brad, Brad" a few times. Brad was her boyfriend whom they killed a few scenes before. But she was with Chris and not Brad so she should have called for Chris instead of Brad.
Revealing mistake: When Danny DeVito brings home the 'bigger dog' he says for the new dog to go eat the little dog that always bothers him. He lets the dog go and the dog goes after the little one. But when they show the dog chasing the little one he almost runs right past him. There must have been a trainer on the other side of the set calling the dogs to come over because he wasn't chasing the little dog. (00:40:30)
Continuity mistake: During the big finale, David's son is seen floating in the pool. A minute later his son runs unto the deck and jumps in the pool where he already was. (01:33:35)
Continuity mistake: In the scene where the Volkswagon is sinking in the water, the first shot shows Chuck Norris diving off the car roof and he starts to doggie paddle. The next shot is of Melody Anderson swimming and behind him, Chuck is still on the roof of the car. The next shot, he is back in the water again.