Comparing a movie to the incredibly divisive The Blair Witch Project will often earn a critic derisive snorts. And yet it's impossible to ignore the comparison when talking about the highly buzzed Paranormal Activity. Ten years since Blair Witch, here comes another independently made, super-cheap, handheld camera film that is clearly a blockbuster in the making. And just as Blair Witch cleverly played with marketing and buzz by pretending to be based on a true story, Paramount has brilliantly pitched Paranormal Activity as a viral movie, a film that they've played in midnight screenings in college towns across the country and instructed fans who wanted to see it to join the movement to bring it to their city. The incredible new marketing concept paid off as the film, reportedly produced for $11,000, made more than that PER SCREEN this past weekend and brought in over $7 million at the box office. But, wait ... is it any good? Has all of this been a smoke and mirrors campaign a la Snakes on a Plane and the actual film isn't worth it? Luckily, that's not the case. Paranormal Activity is one of the most effective horror movies in years and a film that sets out to shake you and, with only a few flaws, does exactly that. The faint of heart need not apply.

To be fair, I think even director Oren Peli would admit that half of the battle for your fearful heart was won before they even shot a frame of Paranormal Activity. The set-up is pure gold. There's so much room for horror right there in the concept that it would have been difficult to screw it up. A young couple named Micah (Micah Sloat) and Katie (Katie Featherston) believe they are being haunted. In fact, Katie thinks she's been haunted most of her life and Micah, the man who has been dating her for a few years and just moved in with her, is just now being introduced to this poor, troubled side of Katie's life. From the beginning, Peli wisely destroys one element of the haunted house movie that usually frustrates the viewer. Most ghost story movies never answer the question – if the house is haunted, why not just leave the house? In Paranormal Activity, it's not the house, it's the girl, and leaving will get them nowhere.

So, Katie is haunted by “something.” To prove it and to get the bottom of what that something wants, Micah and Katie set up a camera in their bedroom. The entire film is seen from the perspective of this camera, giving the viewer the impression that they're watching some horrific surveillance video from hell (the opening frames thank the families of Micah and Katie and the San Diego Police Department, as if these are real video recordings from a real-life incident, and one that we know won't end well). The days are relatively incident-free (at least at the beginning), but when the title card comes up that reads "Night #1, #3, etc.," we the viewer are instantly on the edge of our seats. The time code in the corner of the screen flashes forward and then stops back to real time and the chills shoot up your spine. We wouldn't be watching Micah and Katie sleeping if something wasn't about to go down, right? Your eyes shoot around the screen, looking for what’s off and the heart begins to race. It's an amazingly effective construct for a horror film and it only grows in intensity. As the nights of haunting go into double digits and the activity intensifies every night, the film turns up the horror heat. We know what happened on night nineteen was INSANE. When the title card comes up "Night #20" and the time code begins, the viewer's mind starts to reel at what could POSSIBLY happen to top the night before.

And then the film tops it. There are moments in the final reel of Paranormal Activity that will rock most viewers. I saw the film with a full crowd and I swear I heard a grown women crying near one of the final nights. It can be that rattling. I generally find little things – a slamming door, a light turning on and off with no one in the room – more effective and find that horror movies often come apart as they are forced to reach an over-the-top finale. The unknown is far scarier than the loud. The highest praise I can pay Paranormal Activity is that, at least on a pure scares level, it never comes apart. It's effective up to the final shot.

But could it have been more effective? The concept is so well-devised that you have to start thinking if Peli and his actors really do the most with it. The nighttime scenes rule but the daytime ones are a little forced. Featherston and Sloat are likable but never completely believable. The film suffers like all handheld films from the suspension of disbelief that we need to believe that Micah would really be carrying a camera around that long and not just screaming and cowering in a fetal position. And the daytime scenes allow real world questions to sneak in. They call a friend and a psychic but the activity gets to the point that you'd think they'd call the cops. Or somebody with something more powerful than a Ouija board. And, yes, it's Katie that's being haunted, but wasn't there some place safer they could have gone? Wouldn’t a haunting be a little less scary if you were hanging with as many friends as possible while you tried to figure it out? I wish the overall plot, the dialogue and the characters were as consistent as the hook and the horror, but Paranormal Activity is certainly one thing that most of its genre has not been for the last few years -- actually scary – and that’s ultimately what really matters. Don't say we didn't warn you.

Rating: THREE BONES