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: 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: Men of the Department of Sanitation are picking up Lita's body from her house. The body bag she is supposedly in moves so easily, you can tell it is very light and contains nothing very heavy, much less the weight of a body. (01:03:05)
Revealing mistake: When Millie jumps on her shop teacher's back, the teacher switches from the actor to a stunt double as they begin to tumble about. Noticeably, his hair suddenly gets much darker and has less gray in it. You can also get brief glimpses of his face, and it's obviously not the actor.
Revealing mistake: Throughout the movie, there are mixtures of real snowfall and artificial flakes. When John is at Paul Carnury's house, in particular, the "fake" snow is quite apparent. John could be standing outside in the snowstorm yet little or no snow hit his jacket. (At one point, a few flakes land on top of his head.) When John breaks through the front door, a gush of "flakes" come inside and the ones on the back of his jacket fly and/or roll over his body. "Snow" even bounces upwards off his jacket. (01:13:34)
Revealing mistake: During the first chase, when the Batmobile joke is said, skidmarks from previous takes are visible on the road.
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: 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: The Uber car's instrument panel did not appear to be functional (indicating it was fake). On the driver's side, the numbers in the two large circles were not discernable, but one had to be the speedometer. On the left side, the arrow pointed to maybe 6 MPH, even when the posted speed limit was 60 MPH. The gauge on the right side stayed at the bottom of the left side at zero. (00:09:50 - 00:13:05)
Revealing mistake: After the kids take their seats at the game, the people behind them change, indicating the use of a green screen. (00:13:00)
Revealing mistake: Near the beginning of the movie, there does not appear to be a curtain (or window) on the left side of the screen (e.g, when Samantha is sitting on the couch), but there is near the end when Chloe enters the now-empty room. The use of a green screen seemed apparent throughout the movie. (00:04:19 - 01:23:04)
Revealing mistake: Tom drives at least two differently equipped Ford 4x4 Supercrew trucks. In particular, there are two different grille guards, with one being smaller and less protruding than the other, as well as less-menacing looking. Although inconsistently used, the switch to a grille guard that can cause less damage is used at the gas station when Tom runs into the guy who tried to help Rachel get away from him and when ramming the rear-end of Rachel's Volvo. One truck has fog (or running) lights below the grille guard, making the two differently-equipped trucks more noticeable/discernable.
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: The green screened scene behind the ticket collector on the dock isn't moving. The waves on the water are paused, then the background is moving again in the next scene. (00:08:00)