Factual error: The solar panels (or mirrors) are facing away from the sun. The sun's position can be estimated from ground shadows and object highlights and the panels are facing in completely the wrong direction. (01:11:40)
Continuity mistake: By the end of the movie, when Lucy is sitting in the chair and her skin turns black, we can see her arms slowly turning black as well. When camera cuts away and shows Lucy from behind, her arms are naturally white again.
Deliberate mistake: Despite taking place for at least three years (prior to the arrival of Thomas) in an isolated post-apocalyptic setting, the boys in the Glade have professional looking hairstyles, not the least of which are Minho and Gally, who both have short hairstyles that look evenly cut and professionally maintained.
Visible crew/equipment: When Harry and Lloyd first arrive at the Ken Convention in El Paso, there is a shot of the building. Lloyd walks into the building, opening the door. In the reflection, a large light can be seen, as can some of the crew.
Audio problem: Murph's dialogue doesn't sync with her mouth at the lines "you hate farming, Dad." (00:17:43)
Other mistake: In the final scene both at the start when Fletcher is walking on stage and in a shot during "Caravan," just after Andrew mouths FU, when Fletcher puts a hand under his jacket the shot goes forward and then immediately shows the same footage in reverse. (01:27:55 - 01:32:45)
Continuity mistake: When Penny prepares to lay down on the ice next to Judd, the back of her sweater is already wet from previous takes.
Continuity mistake: When Andre and Chelsea are talking together on the subway train, the extras behind them constantly change back and forth.
Revealing mistake: When Viggo pushes the car off the edge and it hits the ground, as it rolls you can see that the engine/transmission, drive shift and tank have been removed. (01:26:00)
Other mistake: In the book Hazel is reading near the start of the film, the word 'to' is used 4 times in a row.
Continuity mistake: When the family turn off the museum electrical system and then run away, their shoes are dry and do not leave wet footprints on the floor. Only when Millicent checks the electrics do the footprints appear.
Other mistake: At end of movie where there are captions describing how the lives of everyone turned out, for Louie it says "after years of SERVERE PTSD..." instead of "severe." (02:10:25)
Factual error: After fixing Emily's car, James explains to her that someone must have poured sugar in her gas tank, and besides cleaning the gas tank, he will also have to replace the fuel filter and the carburetor. That would simply not happen: As several tests show, 'sugar in the tank' is a complete myth that will not cause any engine problems. If anything at all would happen, it would clog the fuel filter, but never destroy a carburetor. And even if it would, it could not on a Emily's car - since it's a Fiat 500 and (like all modern cars) it has fuel injection, and does not even have a carburetor. (00:14:00)
Revealing mistake: When the 13-year old boys are "driving" the car to chase after Echo, the car is not being driven at all (but on a tow-truck) because we can see that the gear lever is in the "park" position.
Factual error: When they show Alex's partner in the hospital his heart rate is showing 35 on the monitor. His heart rate is not that low from the EKG pattern.
Continuity mistake: On the airplane, the shark bites off April's hand at about the wrist area, but when Fin pulls the gun in April's hand out of the dead shark, the severed limb is an entire arm up to the elbow.
Continuity mistake: When Cheryl emerges from the store and begins talking to the club representative distributing flyers, the lemonade she is holding has the cap off in one shot, then on in the next. It switches hands and then disappears entirely. The flyer she holds also switches hands.
Continuity mistake: In the shot before Josh hands in his preregistration sheet, he is not wearing his cross necklace around his neck. It was in shots prior to that, and is the focal point of the scene with the preregistration sheet. But in the shot where he is just walking, his clothes and all are the same, but no necklace. (00:03:30)
Factual error: During the decompression the plastic water bottles crush. The opposite should happen, as a decrease in external pressure would cause the bottles to expand.
Other mistake: At the beginning, when one bad guy is sitting on a bench with a newspaper, we can read the date October 21, 1959 at the top. But, we also read Nov 3 1970 on the same page, under the mugshot of the Boss being released from jail. (00:04:20)