Paranormal Activity 2

When “Paranormal Activity” hit theaters a year ago, it was constantly compared to “The Blair Witch Project,” and not unfairly. Both were made on tiny budgets with small casts, and both purported to be “found footage” shot entirely by the characters. Fortunately, the similarities end there, for while the “Blair Witch” sequel was a notorious disaster, “Paranormal Activity 2” is a worthy follow-up to its pants-poopingly creepy predecessor.

And hey, guess what, it’s a prequel! Katie and Micah, the couple from the first film, are auxiliary characters, with the focus on Katie’s sister, Kristi (Sprague Grayden), and her family. Kristi’s husband, Dan (Brian Boland), has a teenage daughter, Ali (Molly Ephraim), from a previous marriage, and Kristi and Dan have an infant son together. After their house is ransacked, they install security cameras in every room, which is how the film gets most of its footage. (The rest is from Dan and the others using a handheld video camera, initially for no reason, eventually to document the unusual phenomena.)

I suppose it will not surprise you to learn that eerie things begin to happen around the house. They begin in baby Hunter’s room — alarming in and of itself. (The audience thinks: Movie, you had better not hurt that baby.) They are subtle at first, increasingly less so. The film builds slowly, takes its time, fakes you out here and there, and then delivers the goods. In the meantime, Dan scoffs at the idea of supernatural forces; Kristi is scared; and Ali thinks it would be cool if their house were haunted. The Mexican maid burns incense and crosses herself a lot.

Oren Peli, who wrote and directed the first film, is onboard as a producer this time, with Tod Williams (“The Door in the Floor”) directing. He has wisely followed Peli’s basic aesthetic. Just as before, there are no computer-generated special effects, or at least none that are apparent. Everything seems to have been done practically, as in a live stage show or a carnival spook-house. This has the unsettling effect of making it seem possible that these creepy things could happen at your house, too. Heck, after a while it starts to seem likely.

In addition to being tense and scary, the film actually complements the first one, enhancing the story without having to retrofit too many of the details. Katie’s backstory makes a little more sense now, but isn’t so over-explained that it loses its mystique.

In short, the way “Paranormal Activity 2” succeeds is by giving us another dose of what worked the first time. If you enjoyed “Paranormal Activity,” it seems likely you’ll also enjoy the second one. (By the same token, people who weren’t scared by the first one shouldn’t bother with part 2.) They’ve added a baby and a dog to the mix, but the basics are the same. Pleasant dreams!

B (1 hr., 31 min.; R, some harsh profanity, brief violence, a lot of scary business.)