[UPDATE: Click here for our Paranormal Activity 3 review]

October is nearly upon us and that means the annual onslaught of Halloween horror movies – a lineup which, in recent years, has come to include the Paranormal Activity franchise.

Halloween 2011 will bring us the third chapter in the series, the sparsely-titled Paranormal Activity 3. A full-length trailer and some viral clips have been generating curiosity about what secrets and scares this third entry – which is actually a prequel – will provide; there’s also the lingering question of whether or not this franchise still has the necessary steam to make a third film in a tried-and-true formula a worthwhile trip to the theater.

The annual genre movie festival “Fantastic Fest” recently finished off with a surprise screening of Paranormal Activity 3, and some of our favorite movie sites were on hand to catch the screening and have posted their reviews of the film online.

So, if you’re interested in reading some early Paranormal Activity 3 reviews, we’ve posted some review snippets below – Totally SPOILER-FREE for anybody worried about having the movie ruined before they have a chance to see it. Feel free to read on at your leisure:

Indiewire – “Paranormal Activity 3” is less effective than its predecessors, but it still works when and how it needs to. As a prequel to a prequel that further explored the supernatural world created by Oren Peli, the film unwittingly reveals the dwindling supply of ideas left to be injected into the franchise, both in conception and execution, even as it offers a finale mostly worthy of its predecessors.

We won’t spoil any of the film’s surprises, but we will say that the two theatrical trailers released thus far feature a wealth of material that is not actually in the film, suggesting that if it hasn’t already significantly changed, it still might be. But what’s currently in the film generates real, entertaining scares, even if they’re not necessarily best for fulfilling the back story previously established for the girls. This one most actively tested our resistance to character stupidity while still really terrifying us, and further, created payoffs that worked while making the least sense conceptually.

Movies.com –  If you liked the first two Paranormal Activity films, you will most certainly like Paranormal Activity 3…If you haven’t seen any of the previous PA films, you’re not going to be too confused if you make PA3 your franchise entry point, though you will miss out on the context of it all, which isn’t much of a deal breaker considering the PA franchise is already about stretching your willingness to buy into all the spooky nonsense.

The thing that impressed most about PA2 was its ability to expand the demon mythos introduced in the first film without feeling like it was a stretch to connect the two, and it’s exactly what impresses most about PA3.  Returning screenwriter Christopher B. Landon does a commendable job of further defining the unique relationship these two girls have with the unseen thing that goes bump in the night, though unfortunately most of that comes in the film’s last hurrah.

HitFix – It is effective, no doubt about it.  Joost and Schulman were the filmmakers behind “Catfish,” and this film manages to play its tone fairly realistic.  I like their use of ambient sound, and I think they stage many of the scares very well…The film makes a few big moves early on, and then as it progresses, it definitely keeps turning up the intensity and the reality.  I have some logic issues about why certain things are being filmed and who’s doing the filming, issues that are somewhat inherent to the idea of a found footage movie, and I have some other questions that have to do with continuity between the movies.  But overall, it feels to me like this is exactly the sort of escalation that has to happen for audiences to walk away happy after this one.

The last ten or fifteen minutes of the film is where they really let it all swing, and it’s a lot of fun to watch how they stage it and how they play it and what the reality of the film is.  Some of the jumps are predictable, but they throw so much at the audience that it feels like they just plain want to please.  If this was the last of the “Paranormal Activity” films, it would feel like they’d pretty much wrapped it all up.

As is noted in the reviews, the film – and the cut that the reviewers saw at Fantastic Fest – is still in a state of flux, whereby what has been viewed in the trailers, as well as this early screening, might not be the same material that ends up onscreen in the theatrical cut. This was certainly the case for the ending of Paranormal Activity 1, so take all these impressions with a grain of salt for now.

That said: It sounds like PA3 will be, if nothing else, a fun freaky film to watch during the Halloween season. How do you feel about these early reviews?

Paranormal Activity 3 will be in theaters on October 21st.

Sources: Click any of the site links above to read a full review of the film.