As a guy who has seen every episode of Buffy, Angel, and Firefly, The Cabin in the Woods was likely to be a home run for me. Joss Whedon co-wrote and produced the film with former Buffy and Angel scribe Drew Goddard co-writing and directing the film. Normally, I'd say that was a recipe for success.
To be clear, there are things to like about The Cabin in the Woods. The scenes with Bradley Whitford, Richard Jenkins, Brian White, and Amy Acker were all great and really funny. Whitford in particular was probably at his best since The West Wing went off the air. Goddard and Whedon also have a lot of fun with playing with and against genre conventions. Theirs is an inventive and dexterous screenplay. Unfortunately the cost of that inventiveness is that does away with some of the suspense that could have been otherwise present had the government angle not been present at the onset of the film.
I knew virtually nothing about the film going into it. Up until the week following its release, I had barely seen web banners advertising The Cabin in the Woods. I hadn't seen a trailer. I didn't know that Joss Whedon or Drew Goddard were involved in a film that was coming out, let alone this one.
The weird thing is The Cabin in the Woods is basically just like an episode of Buffy or, given its darkness, maybe Angel. Its plot could easily have happened within the confines of either series. The issue here is that within the confines of either series you would have cared what happened to the characters in events that transpired. Aside from perhaps the heroine, there is little in the way of caring what actually happens to the characters. This doesn't make the film unenjoyable--it is certainly an all right time--but it might be best to temper one's expectations for just that, an all right time.