Not the 'rollercoaster ride' of fear shown in the trailers...

Rating: 7/10 (2 February 2010)

The trailers would lead you to believe that this was a non-stop, scare-a-minute horror film and although it's not, it's still a worthy endeavor.
The problem of course by misleading movie audiences is that those who went expecting this to be more than it was are going to be very disappointed. Thankfully, I didn't buy all the hype and since I didn't drop $10/person to watch it, I was a bit more open minded.
The style of the film will also be turn-off to some, particularly those who don't care for the 'amateur look' with camera shaking, etc. which has been used in The Blair Witch Project and Cloverfield to name a few. When done well, it takes it out of the realm of being a professional production and makes it more 'real', but it's not for everyone, especially those prone to being motion sick.
The reason the film worked for me was all of the subtle effects used throughout the production. A lot of the atmosphere was created using only off-camera sound and by what you couldn't see. Even the effects, which were very low key, were quite successful in making my skin crawl a few times.
Although I too love gory movies (especially anything with the undead), I feel it takes a bit more creativity to deliver a scare without a hatchet-wielding psychopath or torture devices used on its hapless victims. The fear in Paranormal Activity is not a physical form like Freddy, Jason, Mike Myers or any numerous horror films and remakes of late, but more by what we don't know or understand.
I'm not going to try to defend this film by those who say it sucked or want to degrade it. That's OK with me, because I can certainly see the talking points against it. What's interesting is that (2) people I know that didn't like it and rented it recently, were occupied doing other things while it was on and weren't paying much attention. Is that good or bad? Was it so boring they lost interest or were they so preoccupied that they didn't play close attention to all the details? All I can say is that worked for me.