Jack Nicholson: Yes or No?
Here and elsewhere, I've heard people say that Nicholson was miscast, that he's so creepy that there's no surprise when he turns murderous. They say that the movie would be scarier if a nice guy were corrupted by the Forces Of Evil. But *I* say that if Jack isnt creepy and it isn't obviously a terrible idea for this dysfunctional to be snowbound and isolated for months, then the first act is totally boring!
Seriously, the reason the film is scary is that everyone has an Inner Child inside, whose greatest fear is the parent turning against the child. A father who is creepy to begin with and who is easily corrupted is much scarier than a father who resists the evil ones.