Rating: 
Not as bad as the second one, and almost as good as the first one
The first Paranormal Activity was a huge success, merging a camera-based blair-witch-like atmosphere with an in-house-ghost story. The studio soon realized that it “needs” a sequel, and the second part was created that didn’t really bring anything new to the mix, and it’s general mood and execution was lacking. Now we have the third part, and it still doesn’t bring anything new, but this time it’s done with a lot more attention to detail, and some parts can be called “quite” creative too.
Knowing how the first two parts ended making another sequel would’ve been pretty stupid, so as usual with such cases they decided to make a prequel. We go back to 1988, with it’s cheesy beta cameras, interlaced images and weird hairstyles. The girls would later become famous for being in movies (paranormal 1 and 2), but right now they’re just kids talking to their imaginary friends.
So is it a witch covent? Is it the devil? Is it casper the friendly ghost? Who you gonna call? Ghostbusters? Nah, probably just a pizza delivery guy, but this still works as a somewhat scary movie, and judging by it’s gross revenue people like ghost stories if they don’t happen to them.
I’ve seen better.