Continuity mistake: In the scene where the two men are carrying the coffin with the cross on it down to the crypt, the coffin is being held with the cross pointing towards the last man. But in the next shot the cross is pointing towards the first man, as the coffin has been turned around. Then in the next shot the coffin is in its original position, with the cross pointing towards the last man. There is not enough time for the coffin to rotate this many times between the two men carrying it.
Continuity mistake: When Theo and Eleanor decide to explore the house, before the arrival of Luke and Dr Markway, they are in one of the dark corridors of the house. When Eleanor speaks the leaves of a plant shake, close to her right shoulder, but Eleanor is standing perfectly still, touching the right hand side of her chin with her right hand. Eleanor then hears a gasp, and we hear her thinking. In the next shot of Theo, Eleanor, now in the background, has moved a meter or two away from the plant, she is more to the centre of the archway. The next shot shows Eleanor standing next to the plant again.