Imagine it. It's been years since you saw the last zed. Your little band of survivors is now a thriving town. You go swimming in the local pond and discover that the bottom hasn't been totally cleared yet.
Fast zombies duh. if slow zombies came at me id just speed walk and get away. now a fast zombie who can run at full sprints is a scary fucking thing they dnt get tired or sore from running. Id rather go against slow zombies anyday over fast ones. Fast zombies=every1 dead