First, I recommend seeing it. I'm not going to tell you anything about it.
A few warnings, though.
It's shot with a handheld video camera. If the Blair Witch Project made you feel dizzy or nauseous, this probably will too. I've been told if you take Dramamine, it will help. Because of this, don't sit too close to the screen. I generally sit closer than most people, but I knew this was all handheld, so we sat much further back. I'd sit as far back as you can. It will help. If you're very sensitive to this type of thing, it might be best to wait for video.
Reactions to it from audience members were very similar to back when I saw Blair Witch-- People either got it and loved it, or didn't and hated it.
I liked it a lot.
It's much funnier than you'd think.
It was worth my admission price, ($10.50), which is the highest praise I can give a movie in the theater. It wasn't a waste of the cash.
I don't want to talk too much more about it, because I don't want to spoil it.