Revealing mistake: When Bert is running in the woods, away from the local guys, he rubs blood on a tree to make them believe he ran a certain way. Look close, the tree already has red tint on it probably from previous takes that didn't wash off. (01:04:35)
Revealing mistake: The scene of rioting in the UK features a load of police officers running through a crowd. All the officers shown are wearing black tunics and custodian helmets worn with chinstraps. This is obviously old stock footage from a protest in the 80's or early 90's as nowadays, (and especially in 2012) the tunic has not been worn as general wear for well over 15 years, and Brit cops are now better equipped for protests with body armour, NATO helmets, flame retardant overalls, etc.
Revealing mistake: When the shark bursts through the window of the cabin, in each of the shots facing Brody, including when he shoves the air tank into the shark's mouth, the glistening water is visible in the window's reflection behind Brody. The shark's reflection is never seen behind Brody, despite the shark's massive size in the small cabin. Bruce must have had the day off during Roy Scheider's takes. (01:58:00)
Revealing mistake: In the library scene when Richie sees Pennywise the clown, all the balloons filled with blood are popping on people who aren't supposed to be able to see them, but one lands on a lady and you can see her jump as the balloon pops.
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: When Ariadne is pulling the two huge mirrors close together underneath the bridge with Cobb, watch her when she is closing the second mirror. She steps over something even though there is nothing present for her to step over. There must have been a green screen frame there for her to step over.
Revealing mistake: While Bishop and Steve McKenna are practicing with various firearms, a slow-motion shot in the film of Steve shooting a .50 caliber rifle shows that, while the sequence depicts him firing "live" rounds, the extracted shell casing is from a "Blank" cartridge (evidenced by the crimped forward portion of the brass casing). (00:34:15)
Revealing mistake: When the spear handle is protruding from Hector's shoulder, the area of the armor around the circular wound is clearly visible and it is in perfect condition. There is no tear in the armor whatsoever, around the wood, which would have been necessary to allow the wide spear tip to penetrate the armor and actually enter Hector's body as it did. (02:01:20)
Revealing mistake: Mr Hyde makes no bubbles when growling underwater. (01:11:30)
Revealing mistake: When Rob is in the Cafeteria eating all the coleslaw, he yells "I'm the coleslaw king of the world!" there is a girl in the background who mouths it as he is saying it. (00:50:00)
Revealing mistake: In the visions of Nefertiri scene where Nefertiri is fighting Anck-su-Namun back in ancient Egypt, Evie (Nefertiri) gets knocked to the floor and when she lifts her mask up you can see on her right index finger is a band aid/plaster. Did they have plasters back in ancient times? (01:07:49)
Revealing mistake: The Senator's Corvette explodes before it hits the ground. (00:09:10)
Revealing mistake: When Yoda knocks Darth Sidious backwards over his chair, you can see the stuntman's hand. Sidious's hands are old and his nails are dark around the cuticles, but the hand during the flip is perfectly healthy and a different size. (01:45:35)
Revealing mistake: When Will Smith throws a rock at the escaping Edgar alien, if you watch the rock after it hits the alien, it disappears after hitting the ground. (01:23:20)
Revealing mistake: When Woody falls out of the closet wrapped in the string lights he hears Buzz's voice, and in the next shot as Woody sneaks up to Hannah's room we see Sid's open door and doorway, which looks perfectly normal. However, after Woody rescues Buzz from Hannah's tea party they both stop in the hallway, and there's another shot of Sid's open door and doorway, only this time it's not normal to say the least. Five of the six hasps, bolts, and locks that should be (and normally are) screwed into and attached to the inside of Sid's door (one hasp mechanism, third one down from the top, is attached to the door's frame) are now actually kind of floating there in mid-air right beside the doorway, as if there's an invisible door there. Weird that Pixar artists deliberately did this, but it's bizarrely funny to see.
Revealing mistake: When the huge alien ship settles over the White House there is an exterior wideshot of the grounds. At the bottom of this shot it's funny how there are many tourists - adults and children, just milling around in front of the gate and across the street with a van driving along between the two sides, and not one has any sort of reaction to the alien ship. This real shot of the White House (some shots had smaller-scale models) had the CG ship edited in during post production. (Visible on fullscreen DVD.)
Revealing mistake: When the kids step out of the water and walk towards the house, the floor is already soaking wet from previous takes.
Revealing mistake: When Jack and Rose are running from the raging water that is gushing down the hall after them you can see the faces of the stunt doubles through the computer generated ones of Leonardo and Kate (slow motion can help but isn't essential). (02:17:15)
Revealing mistake: Near the end of the movie, when Maverick's plane is about to be launched, there is a quick closeup of an F14's nose gear, which is quite obviously not hooked up to a catapult or anything else.
Revealing mistake: When Tony goes to the bathroom and scans his blood toxicity, the Tony who faces the camera is supposed to be his reflection in the mirror, but the problem is the reflection is not reversed because it's not a mirror image, note Tony's clothing. Also, note how he scanned his right hand's finger, but then in the "mirror" he's sucking on his left hand's pricked finger. (00:28:30)