The horror movie genre, while supremely varied, is limited in scope — there are only so many conventions a film can contain without meandering into the distracting.

Haunting perspective · Paranormal Activity 3 follows the harrowing tale of sisters Katie (Chloe Csengery, left) and Kristi (Jessica Tyler Brown). - Photo courtesy of Paramount Pictures

Paranormal Activity 3 pushes these limits, playing host to a wide assortment of horror concepts and mythologies. Poltergeists? Creepy children? Communicative demons? The occult? Check, check and double check. This movie has it all, though none of it’s new.

It’s a wonder, then, that directors Henry Joost and Ariel Schulman have managed to craft a compelling, focused piece out of a buffet of influences and classic horror clichés.

Paranormal Activity 3 builds on the minimalist premise that propelled the first film in the series to acclaim in 2007, this time looking at the childhoods of Katie (Chloe Csengery) and Kristi (Jessica Tyler Brown), two sisters whose adult lives were detailed in the first two films.

As with Paranormal Activity 1 and 2, the main plot is basic enough: Things in the house go from normal to not-so-normal and then to holy-hell-we’re-going-to-die mode, with a frustrating search for explanation tied in. Everything is shot from a distinct point of view — be it a hand-held camera or omniscient perspective — and editing is hidden under a fictitious veil of home video spontaneity.

In that sense, the third movie doesn’t bring much new to the table. You’re not going to be blown away by concept creativity here, and the style and pacing of the franchise make it easy to recognize when the scares are coming, making the result not much of a surprise.

But here’s the thing: Joost and Schulman know this. Instead of letting predictability hinder the film, they’ve used it to their advantage.

Like a rollercoaster slowly clunking toward the apex of a massive drop, Paranormal Activity 3 brazenly taunts your psyche. It gambles, betting that even if you know what’s coming, you’ll be overwhelmed by what actually occurs. To top it all off, the film swiftly ramps up the intensity of the paranormal incidents themselves in a way not seen in the first two films.

This is not subtlety at play here. This is successful shock and awe.

Though the premise might not be anything new, Joost and Schulman reach into the bag of tricks to milk all the terror they can out of it.

It’s the kind of cleverness demonstrated by what might be the best — and most aggravatingly scary — use of a standing floor fan in film to date. Hijacked by stepdad Dennis (Christopher Nicholas Smith) to act as an auto-panning platform for his camera, this rotating, whirring horror is a thrilling success. The view of the camera continuously swiveling from kitchen to living room is maddening, simultaneously hiding and revealing details during already eyelid-twitching stretches of quiet suspense.

Joost and Schulman’s attention to detail is part of what makes Paranormal Activity 3 so fresh. The film could have derailed itself in several instances, including its cheeky references to the horror genre (a hissing, static-filled television being one obvious example) and its hodge-podge thematic mixture of ghosts, possession and cult-like demon worship. But the filmmakers hold steady, focusing on the true guiding purpose of the movie: to scare you by any and all means possible.

The final act of the film takes fright to unforeseen new heights. Be warned: Paranormal Activity 3 is not suited for the faint of heart. It even sent one young woman nervously half-jogging out of her seat at the climax of the movie (“I can’t stand it!” she wailed out of reflex, quickly cupping her mouth.)

It’s all helped by the cast’s surprisingly seamless performances. No one sticks out, and relationships just seem surprisingly natural, particularly between Dennis and the girls’ mother, Julie (Lauren Bittner). Where is this sort of acting in Hollywood’s big-budget films?

Like the original Paranormal Activity, the dialogue, at some points, seems improvised; however, writer Christopher B. Landon must also be given credit for his beautifully transparent script.

Perhaps Paranormal Activity 3 won’t win any awards for originality. So what? It’s still the scariest film of the year so far, with only a few legitimate challengers looming ahead.

Paranormal Activity 3 proves, if anything, execution still trumps a flashy concept. What’s important is that the film giddily delivers on its promise of fright. For that accomplishment alone, it’s worth a watch.