The whole movie takes place in a 1950's-ish universe, full of bright colors and picket fences. And a chain link fence to keep the uncollared zombies out of course. Other aspects of this world include children having a class in marksmanship where they are taught "In the brain and not the chest. Head shots are the very best." People who don't wish to become zombies pay to have funerals with a separate coffin for the head.
Overall this is a very funny movie. It is rated R but it shouldn't be. The reason given for the rating is that it contains "zombie related violence" but honestly, it's not that bad.
This movie is also rated R, mostly for language, though the opening scene is a little distressing. Last time I checked it was available for free on hulu, though you probably have to be signed in so they know you are of an appropriate age to watch the movie.