Starts off pretty funny and then devolves into the genre it was goofing on in the first place. This is a fairly common problem with these types of movies - perhaps it is a limitation wired into the nature of spoofs that also try to be sincere. I'm not sure Shaun of the Dead avoids this, nor does Tucker and Dale. I also have a very limited tolerance for Jessie Eisenberg, so if you don't your results will vary.
One cinematic zombie is much like another and there's no innovation here. It's a case of meet the folks, but watch your back. Convincing main parts as we'd expect given their pedigree, but the script is only just in the land of the living, with more missed opportunities than the myriad of zombie extras.
It's hard to choose between 3 and 4 stars for this film, because despite the cheesy/ non-believable/ American style moments it is so witty hilarious, and well assumed. It is a very enjoyable film, that made me laugh loudly, coming from a person who is not really into comedies.