Continuity mistake: When the girls bring a birthday cake into Judy's room at the first time, her bed sheet is patterned with what looks like flowers but when Judy is fast asleep the next time, the sheets are plain white. (00:52:30 - 01:15:30)
Continuity mistake: Velma adds books to the pile in front of her when she takes the telephone order. Looking down the pile, you don't see any trace of the random loose papers that appear when she hauls the whole lot to the desk with the TV on. (00:06:25)
Continuity mistake: When Max is going to stab Naoko at the end of the movie, he grabs her by the hair, but in the next shot he's grabbing her by the chin. (01:18:30)
Continuity mistake: After Chloe runs off into the woods and the other two girls finally find her after she's had her run in with Slender Man, they are shining the flashlight in her eyes and asking her questions. In one shot her eyes are still open as she gazes near blankly off in the distance. When it cuts to a close up and suddenly her eyes are tightly squinted shut. (00:38:45)
Factual error: When Watson is pinned down by Moran at the arms factory in Germany, he hides behind a large artillery piece. He looks around and sees a pair of hearing protection. They appear to be modern hearing protection ear muffs, wrapped with cloth to make them look period. They have plastic clips to detach the ear cups from the metal band, which gives them away as being modern. They appear to be Peltor style hearing protection.
Continuity mistake: Inside Lord Peel's study, Poirot asks Lady Westholme what did she do after lunch, since "You did not immediately go for your walk, I believe." Peter Ustinov poses the question with his hands behind his back, but Lauren Bacall's answer answers with the stand-in for Ustinov posing with his hand on his hip. (00:54:40)
Revealing mistake: Just after the scene where Mark is killed, there's a shot of Jason's feet as he opens a screen door and walks across a dusty hardwood floor. As the dolly pulls backward across the floor, you can see the camera's roller marks in the dust. (00:59:10)
Visible crew/equipment: Towards the end, when the Dude starts getting angry after Walter accidentally scattered the ashes all over him, you can see a black wire under the Dude's shirt going into his pants, most surely a microphone.
Continuity mistake: Talking with the feds about the case, Cross says "This guy's a collector." Kyle Craig in the background goes from holding a pad to a folder, and then closes it multiple times when it was closed to begin with. (00:24:00)
Revealing mistake: In the scene where Trout's gang burns the school and kills Sam, there is a part where Katherine runs into the sheriff's office then exits. A few seconds later, Katherine runs by a shop on which the name is reversed. Very obvious. (00:51:40)
Continuity mistake: Lady Raven arrives at the Coopers' place and starts talking to the wife. Cooper's watch is set to 1:35. An instant cut later it's set to 1:20.
Continuity mistake: When Jesse brings Reggie home with him, Jesse plays his answering machine as the dog makes himself at home. After Jesse places his gun on the kitchen counter and pours himself a drink, Jessie heads over to the den to listen to Jenn's message again, and he takes a seat in the den. Then, in the last wide shot, the gun is back in Jesse's holster. (00:06:25 - 00:07:10)
Continuity mistake: When Barry tells Ray to go check if the fisherman is alive, Barry's flashlight keeps changing position from his right hand to his left hand. (00:15:58)
Continuity mistake: When Don Knotts is in the old Simmons mansion, he falls down a chute of some kind. If you watch closely you will see the stunt person looks nothing like Don Knotts. It is a younger man with very straight hair.
Continuity mistake: When Julia is explaining the conspiracy to Rick in the stairwell, the position of Rick's hands in front of his face change between shots. (01:03:25)
Continuity mistake: We see that when Pat's host leaves the room, there is a pink bag sitting on the side of the table, to the right of the window. Later, when Pat walks over to the window, the bag is now gone. (00:08:20 - 00:10:00)