Despite them though this is a nice, low key little horror movie that, despite there not being a original bone in its body still does what it does very well. As always with these things the conceit of them never putting the camera down in dire situations is a little forced (though it annoyed me at the time I think in retrospect Blair Witch got away with that better than anything else by making the camera effectively a security blanket for the female character), though at least here most of the action is on a locked off camera rather than being lugged about.
The main flaw was the male character being so deeply irritating (he's repeatedly ignores all advice- except the one time he should have- making the situation worse and refuses to take any responsibility) the ending is as much a relief as a shock. Though I suppose that at least he's the sort of guy who would grab the camera before running to respond to his girlfriend's screams.
The main bonuses are the exceptional use of sound for effect, very nicely done and made a change from the Saw wannabes. The woman gave a great performance as well, equal parts genuine, shit scared and unsettling as needed.
SPOILER! (select to read)That said the big jump in the new ending is done brilliantly.It could have done without the tiny bit of CGI in the last few seconds though, based on what I've read the original more low key ending,
where instead of chucking his body at the camera and going all demon she stabs him to death downstairs and then comes back up covered in blood before standing catatonic for hours, at which point the police arrive and shoot her when they mistake her coming out of the trance in a confused state for an attack, seems more in keeping with the rest of the film. If nothing else it leaves some ambiguity over if there ever was really a demon or if it was just some coincidences/fakery and her being a nut job.
In other news: It's probably going to be shit but the use of the "Shit scariest film" quote in the Descent 2 (which apparently doesn't follow either of the endings to the first one but creates a third) trailer deserves some sort of award.