Paranormal Activity could have condensed all of its "content" and been a perfectly good 45-minute movie. Instead it drags on for 86 minutes. 99 if you watch the extended edition, apparently, though I didn't notice any difference at all until the very end. Or perhaps the extended edition and the edition with the alternate ending are different versions. In any case, they both sucked and both endings were unsatisfactory.
I love a good ghost story. I love a good documentary-esque movie. Not Cloverfield, but Diary of the Dead, hell yeah! Or Brutal Massacre. That was so hilarious, but I suppose that would technically be categorized as a mockumentary. Anyway, my point is that Paranormal Activity is boring because of the complete lack of action. I would say that only 8% of the movie actually includes any kind of action. But when you call it a "horror/thriller" that is supposedly all about a very violent haunting, you expect there to be some violence. And haunting. No. Paranormal Activity saves it all for the last 6 minutes. That is not how you make a good movie. That's how you make a pile of crap.
I was very disappointed. I knew it wasn't going to be fantastic, but I at least hoped to be creeped out or scared. I'm a huge chicken. How in the world did they not creep me out? But sucking a cock the whole time, really.
My recommendation is to just save your money and rent Diary of the Dead instead. At least that's funny and has some wicked action sequences. And zombie slayings.