Wonderful horror!

Rating: 9/10 (31 December 2006)

*SPOILERS HEREIN* I picked up the DVD of this film a couple of days ago. I've watched it three times. This is without a doubt one of the greatest horror films I've ever seen. As other posters have noted, the tension never really lets up. The only moment that really made me laugh is when Holly in the cabin is stretching and falls over. Other than that, nothing struck me as humorous in any way.
The scene where the tunnel starts to collapse shook me a bit. I'm not really claustrophobic, but I swear I felt a bit of panic watching that.
The creatures were excellent. They were thoroughly threatening and single-minded: "kill-eat-protect the community" was all they knew. As horrific as their behavior was, they reminded me of the Morlocks in H.G. Wells's novel "The Time Machine": not truly evil, merely the products of biological evolution catering to adaptation to the environment.
The film has some of the finest production values I've ever seen. From the choice of actors to the monster makeup to the use of green-screen projection and the (few) solid sets, it all came together.
I have to admit that I didn't like the ending, which taken at face-value was a complete downer. I wanted to have at least one of the party succeed, but then again, life itself very frequently hands us a bad hand.