Character mistake: We see the lead driving on the motorway to get to the cottage. She leaves at junction 6 for Princes Risborough. Which means she is on the M40 that goes to Birmingham. When she arrives the host asks about the drive down and mentions the M4. This is a different road entirely, that goes to Swansea.
Continuity mistake: Solomon put the rope around his waist underneath his coat, but when he was walking through the woods the rope was tied over his coat. Also, the knot would start out in the front of his left side but change to behind his back even though the rope was loose (not taut) behind him. (00:01:55 - 00:02:26)
Continuity mistake: While driving to Harper's house, Jordan did not have the sun visor down, but it was down when she was backing up after she passed Harper's house, #237. The sun visor was not down when Jordan was going down the driveway to the house. (00:17:15)
Character mistake: Nolan said, "Everybody knows that no sharks swim in freshwater" and Spencer said, "They don't come into freshwater", but there are freshwater sharks (e.g, river sharks) and bull sharks (not true freshwater sharks) can survive in saltwater or freshwater. Jacob Harper (National Aquarium) pointed out eyewitness accounts of sharks swimming up the Mississippi River and "bull sharks have kidneys that recycle salt" but did not mention the glands near their tails that help keep salt in their bodies. (00:08:08 - 00:29:50)
Continuity mistake: After Ross is shot, he lies on the pavement with his head to the left of the white line, but later his head is to the right of the white line. (His body would not be rotated 180° by police.) His head is on the white line in between this discrepancy. (00:06:38 - 00:09:30)
Deliberate mistake: After Sam freed Gary from being tied up by the aliens, Gary pulled off the cast he got earlier that day and was able to use his left arm as though it had never been broken. (00:45:43)
Deliberate mistake: The number of clicks (sounds) Christine made on the "text to talk" device did not match the total characters she typed. With few exceptions, there were a lot less clicks/sounds than there should have been based on the amount of letters/words she typed. (00:06:40 - 00:15:30)
Continuity mistake: Ron (dad) brings Amanda her dinner. He carries a bowl approximately centered on a square plate. He quickly sets the plate on the table, so does not have time to adjust the position of the bowl. Ron walks away and the bowl is to the far side of the plate, and there are crackers filling the remaining space on the other side. (00:01:20 - 00:01:57)
Continuity mistake: After the teens parked their vehicles facing an embankment (which was about twice as high as the vehicles' roofs), they walked up the hill to the diner (which wasn't visible). Somehow, one of the teens sitting in the diner was able to see James' SUV being stolen, so they ran outside and down the embankment. The vehicles should not have been visible from inside the diner plus the embankment looked different (e.g, varying heights). (00:07:26 - 00:12:24)
Other mistake: When Tess says good night to Keith, the lights in the bedroom are on, but the switch is down (off position) but when she wakes up in the middle of the night, the lights are off and the switch is still down. We see a lamp on the same side as the switch but even if she turned it off manually, being plugged into that AC outlet would mean the lamp would probably be off based on the switch. If the switch was up in both shots, it would be different.
Continuity mistake: Laura's hair was (flipped) above her shoulders when she brought Cody to school. When she was in her car, her hair was much longer, going at least a couple or few inches down her back. Laura's hair was back to its shorter length (above-the-shoulders) when she got to the typing room at work. (00:15:44 - 00:16:06)
Continuity mistake: Ava sees the stack of mail on the table. She sweeps her hand (fingertips and envelopes are off-screen), as she slides the top envelope closer. Ava picks up the top envelope, as if her hand sweep does not move any of the envelopes (and serves no purpose). (00:05:48)
Continuity mistake: As the SUV pulls off alongside the curb, there are trees with orange-coloured leaves on both sides, but the leaves are green when the ladies are talking in the stopped SUV. The leaves from the tree that is about 15' from the curb are right outside the passenger-side windows. (00:10:15)
Other mistake: At the end the camera bulbs would not work as they are electric. This is proven when the music starts after the creature leaves the area. (02:01:00)
Continuity mistake: The top of Brecken's head was close to (within a few inches of) the headboard before his mother brought the pillow. When his mother put the pillow over his face and the camera shifted to a right-side rear view, the upper part of the bed was raised about 45°. When Lang Dotrice (Brecken's father) arrived and sat on his bed, the pillow used to smother Brecken was at least a foot away from the headboard and Brecken's head (still under the pillow) was about a yard away from the headboard. (00:04:05 - 00:07:16)
Continuity mistake: When Joey is talking to Voight about the puzzle box and Voight tells him to "Keep going," pay attention. It's kind of hard to notice, but if you look closely, in the over-the-shoulder shot facing Joey, you can tell that Voight is standing straight, facing Joey before it cuts. When it cuts to the opposite angle, suddenly Voight's body has rotated about 90° (to his right).
Continuity mistake: Before Eamon hung his jacket and hat on the nails, there were three nails close together near the right side of the board. When he was hanging his jacket and hat, there were only two nails, which appeared to have more distance between them. When the camera shifted, there were a couple nails protruding to the left of the hat. The single nail that was on the far left side of the board turned into two nails. (00:04:38)
Plot hole: Mike carried Sophie into the hospital and walked through the halls yelling, "I need a doctor" until he ran into Sophie's Dr. Thomas. Sophie was put on a cot and rolled into a room where Dr. Thomas immediately began examining her. Mike completely by-passed registration, triage, etc, which wouldn't be tolerated at an emergency room. Emergency rooms are highly likely/almost always back-logged with patients, many with urgent conditions yet still might wait hours to be seen by a doctor or nurse. (00:06:45 - 00:07:20)
Continuity mistake: Jenna takes one red cup from the 3 stacked next to the higher stack and returns the two cups to her left (and left of the higher stack). Jenna uses her left hand, supported by her right, to handle the bottle of wine, but the 2 cups disappear after she sets the bottle on the table. (00:19:50 - 00:20:14)
Plot hole: The prosecuting attorney told William, "We've got no video, no photos, no eyewitness except you" and, "Your biggest problem is there is no gun... This case is so paper thin the judge's probably gonna throw it out, and Danny Fetter is gonna be back on the streets... Basically, it's your word against him." William correctly replied, "That's bullshit..." There would still be enough circumstantial evidence (e.g, gunpowder residue, offender placed at the crime scene) to acquire a conviction. (00:10:03 - 00:10:45)