(at around 4 mins) Near the beginning of the film, we see Ashley painting a girl in red on the wall. We see that Ashley has painted the girl fully in red, however, in the next shot we see that the girl has a white space where the red paint was before.
(at around 34 mins) When printing out the picture of the symbol the computer says "printing 2 items" when it was only told to print one. Also, when the printer prints the picture, only one paper comes out.
Ellison writes two sticky notes & pastes them to a photography of his attic. One of the notes says, "Box of films, how did it get there" (in his handwriting), and the other is a picture he drew of a box. When he looks at the photo and 2 sticky notes later on, the handwriting on note #1 is different, and the hand-drawn box on note #2 is also different.
When Tracy is preparing coffee for Ellison, the amount of liquid in the french press varies - initially the press is filled less than half way, but afterwards when she is pouring it into a cup the press is almost full.
When the girl lifts the ax, her momentum is raising it to strike a blow but in the next shot she holds it horizontally in both hands, at waist level.
(at around 21 mins) Ellison initially goes to call the police after watching "BBQ '79". However, you can not get traditional operator assistance from a cell phone. You can get assistance from an operator within your network , but they would not answer "operator" when dialed . This greeting can only be achieved by dialing "0" on a land line.
(at around 14 mins) When Ellison loads the film projector for the first time, he loads the film on the take-up reel arm, threads the film from the bottom reel and runs the projector in reverse. All other times throughout the movie, the films are loaded correctly from the top.
Pennsylvania's county sheriffs departments do not conduct routine patrols. Their main focus are courts and prisons. The Pennsylvania State Police conducts patrols in municipalities that do not own their own departments.
When Ashley is bringing Ellison his coffee, she knocks on his study door and he opens it outwards (from his side). All interior doors in homes are supposed to open inwards because their hinges are on the inside.
Any differences in the Super 8 footage when viewed multiple times can be explained by their supernatural nature.
(at around 8 mins) Ellison finds a scorpion in the attic of the house when he first ventures up there. We find out later that the house is in Pennsylvania. Scorpions, mostly found in subtropical climates, are not native to Pennsylvania. When Ellison mentions it to the deputy, he reacts as if it was a normal occurrence, rather than pointing out that it would have had to have been planted there.
(at around 1h 30 mins) Ellison retrieves firewood from outdoors, where it is raining, and then proceeds to make a perfect, non-smokey fire. This is impossible given the humidity that would have seeped into the wood.
(at around 1 min) In the very first scene after the four bodies are hauled up on the ropes, they kick a while then seem to die. They are all hanging by the neck which holds the head erect. After the one on the right dies, its head droops. That clearly shows that the body is on a hanging body rig. The head would never droop while hanging by the neck.
As Ellison views all the Super 8 home movies, they all have excellent lighting, everything is visible. It is stated that the films were made in the night when the murders took place. Super 8 cameras are unable to record at night with the camera alone, the film would only capture a black haze. For the home movies to have the lighting that they had, the murderer would have had to have the time to order and set up proper lighting equipment around the victims.
(at around 1h 25 mins) The undead children in the attic watching a movie have make-up to make the look decayed. But it is only on their faces, make-up was never applied to the rest of them.
(at around 32 mins) Items, products and family belongings seen in the Super 8 home movies often weren't available in the decades that the home movies are set in. Most notably is the kitchen refrigerator seen in the 1998 'Sleepytime' home movie reel - the model of fridge shown in the home movie wasn't available commercially until 2009-2010.
Just for the record: all the films on the reels shown are STANDARD 8mm and NOT Super 8mm as incorrectly identified in the narrative. The splicing kit used is also for the STANDARD 8mm format. The film projector featured is also a STANDARD 8mm machine. But the movie camera shown at the end of the film looks very much like a Bolex Super 8mm camera that were very popular in the 1970s/80s.
(at around 29 mins) Ellison states that Super 8 was invented in 1966 but this is incorrect. It was launched at the 1964-1965 Worlds Fair.