In the scene where Alice finds Bill's body hanging on the back of the door to the generator room, the producers purposely did not tell Adrianne King what they were going to do to the body nor did they let her see the body beforehand. When she saw the body during filming it was for the first time. The scream she produced was genuine as it scared her badly. Needless to say, that entire scene was shot in one take.
One critic was so angry at Betsy Palmer's role in the movie (which had angered many of her fans), that he published her address in his magazine, and encouraged people to write her and protest her. He published the wrong address.
When Brenda's lifeless body suddenly crashes through the window before a horrified Alice, it's not Ms. Bartram at all. It's none other than Tom Savini, who is also an accomplished stuntman, having donned a nightgown and wig to emulate Ms. Bartram for the stunt.