Revealing mistake: At the end when Katie enters Hunter's room and throws Kristi against the camera, Katie's reflection in the wardrobe mirror shows her in a different position from when she attacks Kristi, to after she drops out of view.
Revealing mistake: Just before Hoffman knocks Jill out, there is no blood on her head or the table. As he grabs her head blood appears on her head just before he smashes it on to the table. (01:14:40)
Revealing mistake: When Alice and Claire land on top of the prison in the plane, Angel pulls a cable across the roof to help the plane slow down. As he pulls it tight the angle at which the camera is at wobbles due to the cable knocking it. (00:31:50)
Revealing mistake: In the first scene in the diner, as Freddy pulls the knife across Dean's neck, look at where the blade should be. The blade should be visible in the small gap between his neck and the handle, but there is nothing there.
Revealing mistake: The guns that the soldiers use to kill piranhas with are actually Nerf Longshots that you can buy at the toy store.
Revealing mistake: When Mike shoots the cop in the beginning you see him fall on a mat to cushion his fall.
Revealing mistake: In the scene where Lawrence Talbot and Sir John Talbot are talking, Sir John Talbot is blowing out candles, but they are filament lamps, because the third candle lamp actually goes out before he blows on it.
Revealing mistake: At the end scene when the Sheriff is escaping in the truck away from the nuclear blast, the truck begins to flip through the air. While it is flipping we see under the vehicle and can see the hole they use to launch a post to help flip the vehicle for the stunt. A brief puff of white smoke also emanates from that hole briefly during the flip.
Revealing mistake: When Dale is firing the nail gun, hitting the police car, the impact causes sparkles. Obvious movie effect. (00:44:05)
Revealing mistake: When the swimmers are being attacked, some of them are not even panicking.