Nielson plays a man actually in charge of his senses even though he is warped enough to kill a beautiful lady in his wife. The two monsters who enter his house really are there as evidence by the camera catching them on the TV monitor or at least catching their shadows. Holbrook OTOH plays a man who thinks to kill his beautiful lady spouse but it turns out the murder was just a mental illusion he had. Distressing to see such a stalwart type as Holbrook simply mentally hallucinate like that. I hope he told actress Adrienne Barbeau off camera that he really would not have really wanted to shoot her like that cause in the film he plays someone so insanely thrilled to do so.