(at around 14 mins) At the beginning when Dalton falls, after trying to turn the light on, Josh runs up to go see if he is okay. When Josh is sitting on the couch playing with his newborn his shirt is untucked, unbuttoned, and he has no tie on. When Josh reaches Dalton to pick him up, his shirt is tucked, buttoned, and has a tie on.
(at around 27 mins) When Josh Lambert goes to the front door to investigate, he flips on the porch light, which blows immediately. Moments later, they show an exterior shot of the house with the porch light on and no explanation as to how it was replaced.
(at around 28 mins) When the alarm goes off and Josh runs downstairs the front door is wide open and the porch beyond with no screen-door, something that was present earlier when he opened the door to look outside after the knocking. After he has gone around the house checking everything out and the alarm goes off again he closes the front door. The next scene is an exterior shot of the house and there is clearly a screen door present again.
(at around 52 mins) The first time Elise and her crew enter Dalton's room, the light switch just inside the door is a regular Decora® on/off switch. When they later set up to try to communicate with Dalton in his room (at around 1h 1 min), the light switch has changed to a circular dimmer switch, presumably to serve Elise's line to dim the lights.
(at around 30 mins) On the chalkboard behind Josh is a sketch of the Jigsaw puppet's face. When he wakes up, about two minutes later, the drawing is gone. However, there's a scene in between which clearly sets the "second chalkboard" on a different day, beside the fact that Josh's clothes and the names on the detention list are completely different.
(at around 1h 6 mins) When Elise and Specs are performing their astral projection and communicating with the demon, there is a man with a handheld video camera walking around behind the cast. This is Tucker, Elise's bearded assistant, who is filming the process. Only four are seated at the table during the communication.
(at around 1h 35 mins) Towards the end of the movie Tucker and Specs are outside loading their van with equipment talking about writing a novel. If you watch closely Tucker is mouthing Specs lines as he is saying them.
A spelling mistake in the end credits lists John Darko for "Still Photographer/Additional Photagraphy"
(at around 1h 15 mins) When Elise lulls Josh to sleep with a metronome, the metronome reads 60 beats per minute when in fact the tempo heard is closer to 85 beats per minute.
When Josh and Dalton are swarmed by people in the Further and the electricity of the house begins to go out in the living world, we hear the bulbs shatter. However, some of the lights that go out are clearly candles or other non-glass things yet we still hear the sound effect for them.
(at around 42 mins) When Renai Lambert walks into Dalton's room after her shadow, the camera man's shadow can be seen briefly.
(at around 19 mins) When Josh Lambert is upstairs in Dalton's room, he goes to the dresser drawer to grab clothes for Dalton. When he bends down to grab the clothes, you can clearly see his microphone cords.
(at around 1h 22 mins) When Josh Lambert is walking towards the red door, up in the attic in the dream world (spirit realm), a dimly lit man can be seen moving about and pumping fog out of a fog machine in the bottom left side of the screen.
(at around 39 mins) As Renai walks into the room Foster is sleeping in, to the left of the clock in the hallway, the camera's shadow is clearly visible on the wall as it follows behind her.
When Elise first sees the demon, she describes him to Specs as having eyes that are "like two black holes," and has him draw a picture as such. Also, Dalton's picture of the demon is that of a red face and two completely dark spots for eyes. However, when the demon appears in person, his eyes have extremely constricted pupils, and at other times the eyes of a cat.