The film breaks the 4th wall by having the characters reference that they are in a movie. Early on they hear the movie theme song on the radio and refer to it as the theme song. Near the end, they make references to the script in a throwaway joke.
This could have been a good horror movie or a good comedy, but the mix of the two is completely uninspired. It has nothing new to add. There is almost no suspense, which is the point of a horror film. The only thing I liked was the quirky characters and this just wasn't enough.
Better movies like this are "Shawn of the Dead" and "Cockneys vs Zombies", both of which are pretty entertaining and give us interesting characters. Maybe the British know how to mix humor and horror.
Rating: D. Don't waste your time.