Continuity mistake: The clocks are not coordinated, affecting the time frame. Josh and Jen are decorating the Christmas tree at 8:08 PM. Josh goes to his room, "past his bedtime." Josh writes his list for Santa. At 7:15, Josh hears a car drive up, so he looks out the window. Dad meets mom in the driveway and says, "It's almost midnight." (00:05:29 - 00:07:58)
Factual error: Russell said he served twenty-one years in prison because his last offense - possession of 30 grams of marijuana with the intent to distribute - counted as his "third strike" under California's "Three Strikes And You're Out" statute. When he was on the internet trying to locate his father (instead finding his obituary from 2001), information on the computer indicated it was now 2012. This would mean Russell was incarcerated since 1991 - and further indicates he was sentenced about three years BEFORE California's "Three Strikes And You're Out" statute was implemented. Also, 30g of marijuana is the limit for "personal use", so he wouldn't have been charged with intent to distribute. (00:16:15)
Factual error: The buttons on Keira's twin-set cardigan would have matched the cardigan colour. Light buttons were a cost-cutting exercise many decades later.
Continuity mistake: The cigarette the homeless man offered to Frank had a brown filter but was white when Frank had it in his mouth. (00:39:10)
Other mistake: Glen/Charlie poured gasoline all over the vehicle he killed Sandra in - including its soft convertible top - but the flames stayed around the car's perimeter. (00:50:54 - 00:51:26)
Revealing mistake: Obvious use of green screen for buildings across the street. On and off, the background fades, and buildings appear higher or lower depending on the camera's angle. At one point, the angle of walls behind Rex (Bruce Willis) is at a downward angle, and his head is almost touching the ceiling. (00:06:10 - 00:07:25)
Audio problem: The FBI agent is in pursuit of a suspect in a hospital, once he enters the stairwell he draws his Glock handgun, and a click can be heard for a safety disengaging. Glocks are striker fired, they contain no external safeties that can be manipulated that would cause a sound. A sound can also be heard after the gun is already drawn from the holster, representing a holster draw sound. (00:22:22)
Factual error: In 1915 Tolkien was commissioned as a Second Lieutenant with the Lancashire Fusiliers. He (plus various other officers) is constantly shown in the film wearing bright metal cap badge, collar badges and shoulder titles on his Service Dress tunic and greatcoat. However, in the Lancashire Fusiliers officers did not wear shoulder titles on their SD tunics/greatcoats, and their cap/collar badges would have been in a darkened bronze finish, not bright metal (which was for Other Ranks and NCO's).
Continuity mistake: His pickup truck windows are down during the car chase but once the pickup submerges in water the windows are miraculously up, giving him a chance to escape. (01:21:30 - 01:29:00)
Continuity mistake: Andrei is mentally rehearsing icebreaker lines for his first approach to Ramona. Fake macho Silviu sits by him and puts a blunt in front of him, practically under his nose. Reverse shot, and it's gone. (00:02:00)
Factual error: Laura, Aiden, and Mia often complained about how cold it was in the cabin. Mia kept her jar with the Sea-Monkey on her bedroom window sill - right next to the frosted/iced-over windows. The Sea-Monkey's habitat should not be exposed to direct sunlight and, more importantly, the Sea-Monkey needs to be kept in room temperature water or between 70-76° F (higher for hatching). Mia's Sea-Monkey could not survive under the conditions she kept it in at the cabin. (01:22:37)
Continuity mistake: During Stella and Will's walk, Will's scarf was consistently wrapped one time around his neck, but the length of his scarf on either side varied. The right side was usually much longer than the left side, but the ends were about even other times. When Will was lying in the snow, the scarf ends were almost equal (reaching about half-way down his coat); when he stood up, the ends were far apart. After he fell in the snow, Will got up and adjusted the scarf ends to be about the same in length. (01:25:35 - 01:29:30)
Continuity mistake: After the alien abduction, Emmet plans to lead a rescue mission and opens the gate asking "Who's coming with me?" During the sequence, the shadows change completely. At first he is not casting much of a shadow, then it reaches the metal doors, then it stops midway towards it. (00:20:55)
Other mistake: Moose was narrating what he was writing in his second letter to Mr. Dunbar. There were 64 words, 12 more words after "P.S.", then "Love, Moose." A view of his finished letter showed it was way too short to have included everything he supposedly wrote, and the expected format did not match. (00:26:20 - 00:27:10)
Continuity mistake: During the sign-up for the app at the beginning the girl says "I want to be Sarah." Look at her hair; mostly in front of her left shoulder, just a couple locks on the right side of her face. At the cut, hair behind the left shoulder and a bigger right bang. Camera angles and hairstyles switch again back and forth. (00:02:30)
Continuity mistake: There wasn't much blood noticeable on the axe after it was used to chop off the mermaid's tail, but a little later when the man was carrying it over his shoulder, it was heavily covered in blood and dripping. (00:14:17)
Continuity mistake: While listening to news about the hurricane and the disappearance, Fancy looks at Buddy working in the lawn. She spots him from the curtains as he tosses away a broken piece, but in the following close-up he picks up the bloodstained board by stepping over the bit he already tossed aside. (00:15:35)
Continuity mistake: Gabriela's luggage crashes down the slope into the vehicle of the beefy co-protagonist. During the scene, the bra on the pickup's hood is positioned in an obvious different way (also coming lower onto the fender's arc) between shots. (00:13:00)
Deliberate mistake: Carson's [John Travolta] cat Raymond did not appear to be in the pet carrier when he was running out of the building to his car or when walking to his office and placing the carrier on the desk. (00:02:15 - 00:03:30)
Continuity mistake: Zeke is in the kitchen with his daughter. He is checking out Dick's driving license; in the close-up he is holding it with his left hand, but in the following shot, as she asks him "Where'd you find it?" he is holding it in his right hand. (00:10:15)