The shoe-string budget. The clever democratic marketing scheme. The mythic frightening effects on legendary director Steven Spielberg. Every one of these aspects has aided in the success of "Paranormal Activity," the horror film that's making crazy profits in extremely limited release and will be unleashed upon the movie-going public in a nationwide release this Friday. And the cleverly simplistic concept with abundant scares and disturbia lives up the hype it's been given.

The plot couldn't get any simpler. In a found footage set-up, we meet Katie (Katie Featherston) and Micah (Micah Sloat), a young couple who fear their two-story San Diego suburban abode may be haunted. Micah gets a digital camera and a tripod to set up in their bedroom to record any possible paranormal phenonema and we get to see what it recorded. With the exception of the consultation of a psychic (Mark Fredrichs), who tells Katie "You cannot run from this. It will follow you," that's the gist of it.

The film's cinema verite style won't be able to escape comparisons to innovators like "The Blair Witch Project." But once you escaped that film's hype-vortex, you realized that "Blair Witch" wasn't the frighfest it was made out to be, with the scares and action really being minimal at best. This is where "Paranormal Activity" significantly trumps its predecessor.

After a bit of set-up that gives the film a few moments of drag, "Paranormal Activity" slowly boils over in tension-and-release between the relative tameness of daylight hours and the nighttime footage where evidence of a third demonic house guest with bad intentions becomes more and more apparent. Simple effects, grainy camera work with ominous shadows, nuanced sounds and Featherston and Sloat's convincing chemistry and honest-to-God reactions create a building sense of dread in the film's 100 minutes that will cause sweaty palms and extra-crispy fried nerves.

"Paranormal Activity" does what great horror films should do, forcing you to file scenes away in your head and bring them home with you, whether you want to of not.