The quickie follow-up to last year’s surprise hit Paranormal Activity is sort of a sequel/prequel/software patch to indie director Oren Peli’s camera-POV chiller. But you don’t have to know the first movie to follow Paranormal Activity 2, even though if centers on relatives of the original’s demon-bedeviled couple. A fast-food magnate wires his house for security cams after the birth of his child and a vandalistic poltergeist attack is mistaken for a break-in. Suspense develops via various lenses and monitors, as Mom and her stepdaughter begin to sense weird sounds, slamming doors, and bad vibes around the new baby. The series’ debt to The Blair Witch Project is even stronger here, but with Peli bumped for more mainstream filmmakers, the acting and storytelling rise way above the first movie’s cast yelling “What the fuck?” every time something weird happened. Best of all, there are some genuine shriek-outta-your-seat moments in Paranormal Activity 2 to jumpstart your Halloween.