Revealing mistake: An enraged Cheetah almost literally mops the White House floor with Diana flailing her around with the lasso. Wonder Woman is sent back first into a pillar, which disintegrates from the impact. Very good, but not so good is the other piece of pillar that comes down and bounces like rubber by her. (01:51:45)
Revealing mistake: During the dance number in the airport, Santa grabs a security guard who then starts break dancing. It's obvious this dancer is a stunt double as he's younger and skinnier than the real guard.
Revealing mistake: Emmet held a cigarette lighter, displaying a fairly high flame for a long period of time and even held the lighter sideways in his palm without burning his hand! If it were a real flame, he most certainly would not be able to hold it lit very long and would have burned his hand. (00:24:25 - 00:25:25)
Revealing mistake: When the Protagonist and Neil are walking through the Freeport area whilst the plane is being hijacked, just after the worker fills in the numbers on a keypad and opens the door to the vault, he walks through and is followed by Neil. The Protagonist is shown holding a small cup of espresso and briefly looks around before walking in with them. The interior of the cup can be seen when he does this, and there is no liquid inside of it. (00:40:12)
Revealing mistake: When Ava holds a knife to the gambling woman's neck, you can see the plastic knife bend.
Revealing mistake: When Devil Face cuts J.D's arm the knife's clean. (00:52:47 - 00:53:10)
Revealing mistake: After "Yoga Pants" unlocks a man's mouth gag, the man starts to unlock hers. Yoga Pants bends her head down and the metal rods in the mouth gag expand and slide out of her mouth before it's unlocked. She pushes her mouth gag back in place until the man removes it for her. (00:12:37)
Revealing mistake: During the first chase, when the Batmobile joke is said, skidmarks from previous takes are visible on the road. (00:02:55)
Revealing mistake: The candles on the long dinner table are numerous and clustered, but linear in front views of people seated at the table. Based on how the candles are disorderly arranged, it would not be possible to show a couple or few candles spaced apart in front of one person. (00:05:35)
Revealing mistake: When De Niro/Grandpa falls down the roof and hangs on to the drain, he is replaced by an obvious stuntman with a wig and thinner build.
Revealing mistake: Initially, the gallon plastic water bottle Joey was bringing to Hamby looked almost full. However, the ease at which he raised it into the air (by his head), "hollow" sound made when Matt took it from him, and the way it tilted to the side when being dropped down the hole are indications that the water (and its weight) had been removed for most of the scene. When Joey dropped a plastic bag containing a bologna sandwich, chips, and a soda pop down the hole, it went straight down without tilting.
Revealing mistake: Eden's (or her stunt double's) dismount from the horse looks real, but her jumps off the platform to the ground are so soft with uneven foot landings that she has to be hoisted down. (00:11:11)
Revealing mistake: In the scene where Dave (Alan Tudyk) is brushing off Sid (Tony Hale) at the reunion, the camera from slightly behind captures jaw movements that don't match his speaking, and he continues speaking when there is no jaw movement at all. (01:47:00)
Revealing mistake: When the door is kicked in, it does not sound very loud or like a typical door smashing. An interior view shows the door is about half the width of a standard door and a 3-4' board can be seen falling vertically along the door frame/ wall (then disappears). Instead of hearing someone kicking open a door, the sound more accurately matches what happened: a thin door breaking through a board holding it closed! The "breaking in" scene also has some "stupidities." Stewart (without first trying to see if the door was not locked) uses a cordless drill on the door's lock and a second man then uses his right leg to kick it in (without first seeing if the drill unlocked the door). A third man brought a crowbar, which could have easily eliminated the need for someone to bring a drill or for one of the men to risk a foot/ leg injury by kicking open a door. (00:02:11)
Revealing mistake: The backgrounds during the pawn shop scenes often change, suggesting the use of a "green screen." For example, the grandfather clock was behind the clerk to his left, then not there, but back again. Sometimes shirts are hanging in the front windows but other times there are other items there. (00:47:57)
Revealing mistake: It looked like Theo's gold and white checked shoes were a few sizes too big and wide to make it easier and quicker for Laura to put them on her, but Laura still had some difficulty slipping on Theo's oversized shoes. The material even folded down around the ankle when Laura was putting on Theo's right shoe. (00:03:42)
Revealing mistake: When Cecilia is lifting an iPhone up to her ear, it starts ringing as if she's making a call. But on the screen, you can very easily tell it doesn't say "dialing" or "calling" - it's a timer showing how long the call has been going on. She was already on a call before pretend-calling. (01:42:47)
Revealing mistake: When the shop teacher walks up to Millie at the start of the film and slams the book, as he begins to step in front of her table, you can see him subtly "step down" even though he's on an even floor. Due to technical limitations, there needed to be a raised surface on the floor for the camera, a few inches off the ground. It was painted out digitally, but you can still see the actor step off the platform, making it look like he's "stepping down" on even ground. (Confirmed in Blu-Ray commentary.)
Revealing mistake: The location of and distance between windows on the mobile home should stay the same, but do not. The home's exterior is constructed of vertical boards/slats, which can be used to make a rough estimate of the number (then distance). Initially, there were about 24 vertical boards between the shortest window and the window to its right (on-screen). When David and Anne were close to the house, there were a lot more boards between these windows - closer to 36+. The mobile home was "fabricated". (00:02:18)
Revealing mistake: Although it appears that Edgar (and later Norman) put his eye up to the hole in the wall to look into the opposite room, the eye is obviously fake. Too much of the sclera (white part of the eye) is showing and the upper eyelid is too far above it; the upper eyelid typically reaches or partially covers the top of the iris (colored part of the eye). Also, the eyelashes go downward instead of being curved upward. (00:18:05 - 00:19:49)