Equal parts yucky, scary, and delirious,
The Descent is also clever about its limits, and chilling in its effects. It sets up a specific emotional situation for its protagonist, then turns it inside out, with the help of especially daunting monsters. Suddenly, Sarah can no longer be focused only on her own despair, but must face the worst external threats imaginable.
While the plot is straightforward and eventually predictable -- women in a terrible place get scared, get assaulted in terrible ways, and get tough -- the film is also about trust and betrayal, as well as surprising sources of strength. Exaggerating the usual horror movie gambit, the movie invites you to reconsider genre-based expectations. Sarah finds in herself an unexpected ferocity and an almost frightening determination to endure. What's smart about the movie is that it makes her survival costly. While she's relieved to be alive, she's also horrified by her own change.