I can get behind fast zombies that are infected, I'm with you there. But I can't suspend disbelief if a rotting corpse out of the ground can run like Usain bolt. Side note I would like to see monster stories that follow traditional folklore that isn't well known. Werewolves can revert to human through their true love and vampires can't be seen in mirrors only because silver was used to make mirrors but not anymore so we should be able to see vampire reflections in some mirrors. I think that would be cool if made plot relevant