What makes The Exorcist so enduringly terrifying is Friedkin's patient, clinical restraint. The first hour contains almost no supernatural horror. Instead, we watch successful actress Chris MacNeil (Ellen Burstyn) navigate the increasingly bizarre behavior of her sweet twelve-year-old daughter, Regan (Linda Blair). Friedkin subjects Regan—and the audience—to agonizing, cold medical procedures, including a famously grueling carotid arteriography, emphasizing that science and modern medicine have no answers for the rot taking hold of the girl.
Parallel to this, we follow Father Damien Karras (Jason Miller), a Jesuit psychiatrist stationed in Georgetown who is crumbling under the weight of his mother's lonely death and his own fading spiritual faith. Miller brings a weary, bruised soulfulness to Karras that gives the film its moral gravity. When Chris finally turns to the Catholic Church out of utter desperation, Karras is paired with Father Lankester Merrin (Max von Sydow), an aging archaeologist priest who has faced this demonic entity before in the sands of Iraq.
The climactic exorcism inside Regan's bedroom is an exhausting, visceral assault on the senses. Friedkin famously refrigerated the set to sub-zero temperatures so the actors' breath would be real, giving the room a tangible, icy hostility. Combined with Dick Smith’s pioneering makeup effects, Mercedes McCambridge’s feral vocal performance, and Jack Nitzsche’s disquieting audio mix, the film builds an atmosphere of suffocating dread that never relents.
