Nuh-UH! I cite as my historical reference a book I just read: World War Z: An Oral History Of The Zombie War. A walled city with towers would be perfect. Oh, sure, I know a bunch of you are going to say, "But Bill, zombies aren't real." That's what they said about vampires and Godzilla, too.
I love tower defense games. I’ve always been a turtler.