Revealing mistake: When the kids are burying Gus, his supposedly dead face flinches when they shovel dirt on him.
Revealing mistake: When the terrorists drop the dead body out the aircraft door, look closely at the aeroplane just beneath the door, you can see the reflection of the mat the stuntman lands on, as well as the spotters around it.
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: There is an obvious stunt double for Grandpa during the fight scenes.
Revealing mistake: In one scene, the Penguin is making a "bat" shadow puppet on the ceiling. But there's no light behind his hands. If there's no light, there's no shadow. (01:03:45)
Revealing mistake: Towards the end of the movie where Veronica Roberts hands are tied behind her back, she goes over to the mulching machine to cut the rope free. But as she hits the blades they bend and move like rubber.
Revealing mistake: When Ryback jury-rigs a timed explosive to destroy the helicopter, he uses a tin of paint thinner which is expected to fall off a hand grenade, thus releasing the spring on the grenade. However, when the explosion occurs you can see over Ryback's shoulder that the paint thinner tin hasn't moved at all, and that the explosion occurs inside the helicopter, not where the grenade was placed.
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: During Kenjiro's fight with Phan Xu, Kenjiro cuts Xu's face. This cut goes across Xu's headband, but the headband is still in one piece. The cut is visible above and below the band, but the band itself is untouched. As Kenjiros sword is capable of cutting a steel chain, a piece of cloth should not pose any difficulty.
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 several driving scenes, the cars are visibly higher than the rest of traffic. Obviously a flatbed truck was used instead of a trailer for the filming of the interior shots.
Revealing mistake: When El Mariachi is trying to escape Moco's men by sliding down a wire onto the bus, he first throws the ball-and-chain-weapon over the wire. But then when he slides down, you can see a pulley device that he is using, not the chain. (00:26:45)
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: Right after Jake escapes from Tao's pinning him to the track towards the end, Tao is electrocuted, then falls to the tracks. When he stands up, he sees a train heading towards him. He cries out, sticks up his arms, and is hit by the train. In a quick shot just as the train hits, him, however, it is painfully obvious that it is actually a dummy that was placed in front of the train.
Revealing mistake: During the standoff scene in the shipyard, Crazy Kung drops Tarzan (Tyson) from a magnet crane before reactivating the electromagnet, hoisting him up again. At the points where Tarzan starts dropping and where his fall is halted, you see a hole in the electromagnet and wires connected to the actor's back. (01:06:35)
Revealing mistake: When Sean shoots at Dennis the Bookseller's feet, puffs of sand do not erupt from the ground.