Goofs

In the first Amityville Horror, the doorway to hell was a square opening in the cellar wall. In this, it's a ragged round hole in the floor.

Nancy arrives at the house to find Susan, just before the boating accident. The camera zooms in on the upstairs window (the right "eye") and the window has nothing covering it. The next shot shows the same window now covered by a curtain.

When the evil forces caused the elevator to malfunction, the man inside is shown pressed against the ceiling as the elevator is rapidly descending. The only way this could happen is if the elevator was accelerating downward faster than the force of gravity could pull it. That he should stick to the ceiling is against the laws of physics.

A character's right arm catches fire as they sit in the driver's seat of their car. In angles from the side showing the burning arm, it's either a stuntperson's or a prop stuck between the two front seats: its movements don't quite match the actor's, and in 3D prints it's clearly a little too far away from their body.

When the house is exploding towards the end of the movie, The top center of the house explodes 3 different times. You can tell by the way it explodes that they used the same explosion from 3 different angles.

When they light the lighter after the first séance, John walks by with his lighter but the others are still lit from behind.

After the opening credits as Mr. Caswell escorts Melanie and John into the front door, you discover that the perspective view of the foyer in the background of the doorway is fake. There is a gap between the prop background and the top of the door frame where the side of a staircase can be seen ascending in a different direction than the one seen later in the film.

When the character is burned to a crisp in her car, when the body is discovered, the car remains undamaged by the fire.

When the swordfish flies at the camera (and also when it is shaking, ready to come off), the wire is clearly visible.