'The Exorcist: Believer' brings back Ellen Burstyn in a mix of nostalgia and horror

A half-century after the original helped rewrite the rules of horror and launched a thousand imitators, "The Exorcist: Believer" tries picking up that mantle, with the lure of 90-year-old Ellen Burstyn reprising her role. The nostalgia factor elevates an otherwise slow-building film that maintains an eerie creepiness before fumbling through a slightly muddled climactic act.