Watched it last week with two friends of mine... expected something similar to 'The Blair Witch Project' in tone and scope, but then were pleasantly surprised when we're actually SHOWN what cretures they are running away from. There are some nice creepy moments in the film (cave...) and surprisingly well executed action-scenes.
Oh, last thing I read in this months issue of empire is that there are plans for a US-remake. Not sure if that's needed, but maybe this will point other people to discover the original movie.