The Descent
This movie sits on the fence for me. I'll be blunt: It doesn't do anything for exactly 58 minutes in a 1:30 run time besides build up an almost palpable atmosphere and loneliness in the cave system, forests and cabins. Over nearly an hour an uneasiness builds up as we're introduced to the girls before they go cave diving. I'm a strong fan of atmospheric build up but its overdone to the point of not even NEEDING the last half hour. It could have been made as a full drama, romance and mystery movie for fifty eight minutes and released on sci fi and it would get mixed reviews. The Crawlers as they're called feel tacked on. A last minute thought from the director like he double checked his screenplay and remembered "Oh, shit, this is a horror movie!"
The monsters are intelligently portrayed and use echolocation and look really gross, but they resemble their fantasty counterpart "Goblins" way, way too much. Realism and believability is a direct concern from the director and, as such, nothing is beyond belief. Well, sometimes. The girl's fight the monsters back, the monsters hunt accurately, the combat is primal and feral and its really an intense twenty minutes. Yeah, the crawlers show up twenty minutes before it ends. 3:1 Build Up and Actual Horror ratio. I'm reminded of Session 9 here.
It has a cool atmosphere but annoying characters. Cool monsters but they're gone in a second. Horror is an after thought, and the main idea was paranoia and immersion. This is The Thing without any people or monsters.