Continuity mistake: After Todd Howard knocks out his opponent in the boxing match, the crowd immediately starts throwing cups of popcorn into the ring. The camera cuts to Todd cheering and then an overview shot of his opponent laying face down on the canvas. At that view you can see that there is no rubbish or popcorn or anything else in the ring. Then when the camera cuts back to a side view there is loads of rubbish and popcorn all over the place once again.
Other mistake: Near the end of the movie, in the mansion overlooking the water, James Woods is eliminating the bodyguards. As he shoots the one at the bathroom sink, blood sprays all over the mirror, but the bullet never breaks the glass.
Continuity mistake: Near the beginning of the film, the soldiers are filling sand bags with mud. Beletsky, whose hands and forearms are covered in wet mud, puts down his sandbag and takes out a photo of his girlfriend. In the next closeup shot of him holding the photo, his hands are suddenly clean and dry. (00:11:00)
Continuity mistake: When the angel lands face down in the pool, Michael Knight turns her over and her face is completely dry.
Other mistake: Despite the noise of the demon in the house, the tornado clouds outside, the flashing lights from the demon exploding and the fireworks in the sky - not a single neighbor is anywhere to be seen. Even after daylight breaks the neighborhood is a ghost town as we pan away from the actors.
Continuity mistake: When Jamie gets out of her car, her leg warmers reach down to her heels. In the next shot, they've been pulled up to just her ankles. (00:07:05)
Character mistake: When Modoc is suggesting what type of blood to drink, he suggests pigs blood B-. Swine don't have B blood. They have A and O blood only.
Continuity mistake: When George's wife asks him what made him drive all the way out here, their car is on the back of a large dinosaur at that moment. When it cuts to a closer angle for his reply, suddenly they are on a dirt road.
Continuity mistake: When Molly Ringwald is on the phone at the club and gets approached by the girl in orange, throughout the whole conversation the position of the phone receiver in Randy's hand is wildly inconsistent. (00:09:30 - 00:11:00)
Revealing mistake: There are times in the movie when you can tell Bobo's beard is fake such as when Penny's giving him a drink from a 7-11 and it's peeling off near his right ear.
Plot hole: The fact that Buddy placed the knife and note in the steering wheel of Jerry's car is unrealistic. Buddy first met Jerry in the bathroom after school started and Jerry hasn't gone outside of the school building to his car until this point later in the morning... so there's no way that Buddy could have known which car was Jerry's to pull this stunt.
Revealing mistake: When Frank Bauggs is falling from the building, he is a very obvious dummy. His body limps around too much. (00:50:45)
Revealing mistake: Terri is replaced by a stuntman in a dark blond wig once she puts on her motorcycle helmet outside the hardware store.
Revealing mistake: A bunch of seedy individuals are gathered, weapons in hand. Unbeknownst to them, though, deadly ninjas are creeping by, with all the speed of fast-forwarded footage. The problem, besides how obvious the trick is, is that it also features a visible jump cut; you can see the foliage change position literally from one frame to the other during the same shot. (00:01:30)
Continuity mistake: Rick Latimer is at the bar with his buddies. He spots his ex-wife on a date with the divorce attorney and begins rambling. "This kind of sh. Happens", one of his friends says. The friend next to him, rightmost position, is smoking, and his hand is suddenly raised at the cut. (00:02:45)
Continuity mistake: During the scene when Bobby's auditioning for a part, there's a picture on the wall of Helen Martin (the lady playing Bobby's Grandma). The picture disappears and reappears during the scene.
Continuity mistake: When Dragon is chasing the two thieves who stole the money boxes from Yesan and Carina, Dragon slides down a sign. In the wide shot you can see two men clinging to the wall right next to Dragon. In the next shot the men are gone. (00:13:40)
Continuity mistake: When Frances takes Helen to sleep in the car, he puts her in the back seat from the drivers side. In the morning the camera is looking at her through the the window of the door on which she appears to be leaning. Yet when she gets out of the car later in the scene, there is a canvas draped over the door way.
Continuity mistake: Rowdy's thumb position on the sandwich box changes between the first and immediate shot.