I don't think it's as bad as most say it is. It's a zombie movie. How many more Zombie Movies do we need? Well, Jim thought like most of us, we don't need any more of them. So instead of being "funny," it's just a spoof.
They obviously had a blast making it. And those of us who like zombie movies, well, we get it. Those of you who don't like zombie movies, Shouldn't be watching it in the first place. I guess there are some who think there's more to be said, well, they might not like it. So there.
One more thing, it likely employed a gazillion make up artists. And they did a great job.