Continuity mistake: When the Darkness attacks during Camryn's birthday party, Ileana and Camryn run up the stairs, and as they enter the bedroom the drawing of Thantos that Camryn holds is undamaged. When the Darkness takes Ileana, Camryn stands beside her closet across the room and in the next shot the drawing she holds has burnt edges, though the Darkness was never near her or the drawing.
Continuity mistake: After the twins see a bit of Coventry for the first time, in Camryn's bedroom, when she pleads with Alex not to leave, in the close-up Alex has tears in her eyes and her black eyeliner is nearly gone. When she turns around in the next close-up her eyes aren't even moist and her eyeliner is perfect.
Revealing mistake: After Alex steps off the bus at the same corner as Camryn and Beth, some of the same extras keep walking past in quite a few of the following shots. Two examples are the woman wearing a striped top and black skirt, and the man wearing a plaid shirt and tan pants. (00:09:25)
Revealing mistake: When the witch mother is talking to the twitch twins about receiving a star as a gift from their father, you can see a terrible body double in the daughter's place. The makeup is frightening.