It was fun at times and even a little scary on a rare occasion where some plot point hadn't been telegraphed by scenes earlier in the film or in the trailer. The dialog wasn't good, but it serviced things OK, and the characters actually responded really well and believably to the stress and strangeness of the situation. No one was stupid, which was high praise for a horror film, but there was lots of death because the odds were just really stacked against them really badly. The film had a lot of violence, much of it rather gross, and too much of it was directed against the female characters. There are some shock moments, but the film doesn't dwell on them for long.
I liked it, but barely. I'll probably not need to see this one again anytime soon. It is funny at times, but it's a far cry from "Shaun of the Dead", my current standard for funny horror films.