The Cabin in the Woods is a clever film.
A deconstruction of Horror Movies, it was entertaining and humorous, right until the end when it went off the rails. Which isn’t to say it was perfect.
The fact is, the ending was purest nihilism. Given a chance to actually stop the disaster, the two just kinda lean back and say “Naw, let it all burn.”
It ruins the characters in retrospect, revealing them to be narcissistic psychopaths. They’re not people we should be rooting for, and never were. Disappointing.