The sound is one of the reasons its worth watching it at the cinema, you wont get the full effect of being bludgeoned over the head with a hammer at home.
Thought it ok - not quite Evil Dead, but certainly more enjoyable than most horror is these days.
However, there was something that got me (spoiler):
At the end, when she gets the button in the envelope... I thought a 'neat twist' would be if he'd had a wedding ring in there to propose to her. However, she does get dragged to hell so everything turns out all right