Revealing mistake: When Dracula flies into the room to stop his brides from devouring Jonathan, the board carrying him is visible. (00:34:10)
Revealing mistake: When the kids are burying Gus, his supposedly dead face flinches when they shovel dirt on him.
Revealing mistake: In the part it shows Ash getting sucked into the time portal you can see the wire he is hanging from. (00:02:45)
Revealing mistake: This is toward the end of the movie. The scene where Dr. Giggles has a waiting room full of his victims. If you watch closely, you will see the blonde corpse blink her eyes.
Revealing mistake: When Pinhead is killing the patrons at the club and they are running away to try and escape, you can see some of them laughing instead of screaming like they should be.
Revealing mistake: As Ripley and Dillon lure the Alien into the piston chamber, Morse closes them just in time. Watch closely - he misses the switch. (01:38:15)
Revealing mistake: In the chase scene about an hour into the movie, Robert Loggia is shown entering the Liberty Tunnel, driving on a wet road. Note the vaulted round ceiling of the tunnel. Next, we see a series of shots of him in the tunnel, and then a shot of the sun rising over Pittsburgh as he is about to leave the tunnel. Here is the problem - the sunrise shot is taken from the Fort Pitt tunnel on a different day. Note the dry road, the barriers to the driver's left at the tunnel exit and the Fort Pitt bridge straight ahead. There is no place for the driver to make a left turn out of this tunnel. Also note that the POV is from the left lane. All the Liberty Tunnel shots show Loggia in the right lane. The next shot shows Loggia exiting the Liberty Tunnel and making a left turn from the right lane, causing a pile-up. (01:11:10 - 01:12:20)
Revealing mistake: As the three zombies go rabid at the house party, and McGruder and Thug tear the skin off a guy's face, the switch from actor to dummy is visible. (01:10:55)
Revealing mistake: The opening text describing how London is badly flooded because of heavy rains and global warming is accompanied by an aerial shot of the city. From the level of the Thames it is clear that this wasn't even filmed at high tide, let alone during a flood. (00:00:45)
Revealing mistake: When the attorney Ms. Lawlor is being 'hijacked' by the ghost (we only hear his voice) Grubeck in her car, it is very obvious that a person in a black ski mask and black clothes is driving the car.
Revealing mistake: At the end, when the monster grabs the sheriff and throws him across the front yard, the sheriff lands on his back and his right arm falls into a beartrap. The trap snaps and the sheriff screams in pain, but only one jaw of the prop beartrap actually snaps into vertical position (the opposing jaw remains flat and doesn't move). A real beartrap snaps both jaws together vertically. So, the sheriff's hand doesn't get snapped at all.