I didn't watch the first Paranormal Activity. Those who've watched it and watch the sequel told me that Paranormal Activity 2's story happened before Paranormal Activity. To be precise, 60 days before the story that happens in the first one.
The movie is kind of slow in the first half an hour. Scenes captured on the CCTV day by day were shown, with not much changes. Then as the days go by little by little strange things started to happend in the household. Pans falling down, swimming pool cleaning device mysteriously goes on to the side of the pool and door opens by itself. As the movie move towards the end, more drastic things happens. Which I give it out here because that's the only exciting part about the movie.
Those who've watched the first one told me that it is scarier than the sequel. Well, I haven't watch the first one, so I can't give my opinion here. Overall Paranormal Activity 2 is quite okay. It can only be scary if it's watch in the cinema in the dark and with very good surround sound system. Don't bother to watch it at home if you don't own a very good surround sound system.