Great sites
Revealing: When Chelsea is on the roof of the house and Kathy joins her, Kathy's hair is blowing in the wind, while Chelsea's stays perfectly still, the water in the lake is also perfectly still. Obviously the director had the actors do the scenes separately until we see them both together in which case both characters hair is blowing around.
Deliberate "mistake": In the beginning, the police chief says "The six members of the family were found last night, in bed, shot and killed." As he says this, look to the left of the screen. In the background, the real Amityville house (dark brown with white windows and trim) is shown instead of the house used in the rest of the film. That segment was from actual news footage of the murders from 1974; apparently, the director didn't want to recreate it.
Continuity: Towards the end of the movie after George falls, and the rest of the family is climbing down, we see (from top to bottom of ladder) Kathy, Chelsea and then the eldest kid, with the youngest boy still reaching out on the roof. Yet, in the next shot, the eldest kid and Kathy are on the ground, and Chelsea is on top of the roof again, jumping into Kathy's arms.






