If you don't believe it, The Descent's claustrophobic delights are discussed in detail by hardcore fans on the film's lively Dreadit thread. And yes, it's clear that many found the intensely cramped caving moments far more terrifying than any blood-thirsty beast. User PwninOBrien was among the first to offer such praise, claiming, "The monsters were cool, but the most frightening part for me was definitely the sense of claustrophobia in the tunnel system." Poster jmanof8 (who kicked off the thread) quickly agreed, writing, "Yeah, just the claustrophobia was terrifying... i was literally short of breath almost the whole movie, feeling like i was about to suffocate." Dreaditor LaMeraMera responded, "YES! I had sweaty palms, heavy breathing, and felt nauseated watching them in the tunnels. I loved it." 

Posters continued to praise The Descent's claustrophobic elements, and it seems some fans actually felt the film was scary enough without the creature feature elements. General-Vis is among them, posting, "I thought it was great when they were lost and trapped in the caves and trying to find a way out. Once the creatures turned up I didn't find it as engaging." User Fallenangel152 is among the many fans who share that opinion, chiming in with, "I agree. I love the film, but the first half is better than the second for me."

Whatever side of the debate they fall on, it seems most posters are 100% in agreement that The Descent is a modern horror masterpiece worthy of obsessive discussion — even if nobody's talking about the film's beyond twisted psychological horror theory.