A bit of a mish-mash... but I reckon it works.
Contrary to what a lot of people are saying I don't put this in the "Shaun of the Dead" category at all - people just seem to be doing this because it's a British horror film with a bit of gore and a bit of humour in it. I think that's a bit lazy myself.
Personally, I love this film. I enjoyed the fact that you never get too settled in either horror or humour- there's always something that's going to come along and slap you in the face.
I think Christopher Smith achieved something very different with this film - regardless of whether you preferred the horror or the humour, you can't pigeon-hole it as either a horror-comedy or a comic-horror. It doesn't let you get comfortable in the way that SOTD does - the comedic elements are always juxtaposed to horrific ones, and vice-versa.
If you want to be comfortable, choose SOTD. If not, watch this.