The original Paranormal Activity is the most profitable movie ever made. Shot for $14,000 - which included the cost of the camera, software, and computer to edit on - it went on to gross over $108 million. Of course a sequel was called for, so Paranormal Activity 2 was made and despite the incremental increase in number, this is actually a related prequel to the first film.
The connection to the ill-fated couple from PA is the sister of the wife. She's the 2nd wife to a widower with a teen-aged daughter. They have a new young son and weird things are starting to happen. When their house is ransacked, they install a video security system which documents the...wait for it...paranormal activity over a period of nights. Augmented with camcorder footage including visits from the PA couple, the demonic connection between the sisters is drawn out.
And drawn out is Paranormal Activity 2's largest problem. It mistakes taking their sweet time for building tension. It's well past the halfway mark before the first major incidents happen and the last 10 minutes or so devolve into standard spooky movie tropes. While there are a few good moments of creepiness, the familiarity with the "found footage" genre and too much traditional Exorcist-style shocks undercuts the potential of the material. In trying to make it bigger and better, they ended up making a smaller and less satisfactory serving of shocks.
Score: 4/10. Catch it on cable.