There's something about a chick dripping in blood, a torch in one hand, a femur in the other, and going medieval on a cave creature's ass that just gives me a hard on.
The Descent is just an amazing film. Anticipation and the unknown are what drive this movie. There really isn't much to "see" in the first hour of the movie, but there's still enough reality going on to make anyone tremble in their seat. The scene were they go through a VERY narrow opening was almost hard to watch because I am slightly claustrophobic myself and I could almost feel the walls closing in on me.
Once the shit hits the fan though, it is just a hell-storm from that point to the end. Pure, unrelenting terror. It's well worth the wait just to see the chaos and the ending. The cave "crawlers" are scary as hell. They seem to pop up out of EVERYWHERE, and being they have the ability to climb virtually anywhere, its no surprise for them to just...show up.
The Descent is a film that should, neh MUST, be seen by anyone fascinated in horror. It deals with so many aspects of terror. Death of family and friends, startles, fear of the unknown, fear of isolation. Its all there. You can even view it as a metaphorical film, showing "The Descent" into madness.
From my understanding, the US version DVD has a different "happier" ending, which I strongly suggest you avoid, because the Unrated Original Version's ending is much darker and much better.