This is the movie that purports to be all shot in one take.
That's right - the whole movie is done in one continious take, like Russian Ark. If it all was done for real, it must have been damn difficult to pull off.
But, there are a few places where the director could have easily cut and edited so that that it seems continious and if you ask my opinion, that's what happened.
Still, the effect is still jaw-dropping, as all the actors (especially the lead girl) had to stay in character all the time for LONG stretches of time.
It's basically a there's-an-intruder-in-the-house movie with a single character trying at first to escape and then seeking out who or what is making all that noise upstairs when escape is denied her.
There are some good scares (the Polaroid camera scene is heart-stopping) but on the whole the movie can become seriously tedious as the lead character endlessly goes through cupboards looking for a weapon, staring at hallways and stairs contemplating whether she should go further and just acting stupid, basically.
The ending is also beyond ludicrous with a totally unswallowable twist that seems to be just tacked-on because they could, and basically invalidates the while friggin' movie.
I know there's a US remake, but I haven't seen it. Hopefully, they've tightened the film up a bit and got rid of that stupid ending, but somehow I doubt it. Highly.
Still worth catching if you're a big horror nut and to check out the way in which it was shot.