You cannot kill a vampire with an MDF stake; werewolves can't fly; zombies do not run. It's a misconception, a bastardisation that diminishes a classic movie monster. The best phantasmagoria uses reality to render the inconceivable conceivable. The speedy zombie seems implausible to me, even within the fantastic realm it inhabits. A biological agent, I'll buy. Some sort of super-virus? Sure, why not. But death? Death is a disability, not a superpower. It's hard to run with a cold, let alone the most debilitating malady of them all.