The infection starts. If your lucky you hear about it on the TV before you notice your neighbor lumbering around his yard, gnawing on his own hand. The first thing you must do is size up your opponent. Are they fast zombies that can run as fast or faster than you? Or are they the Shawn of the Dead comically slow zombies? If they are fast zombies I would say you are screwed, but being they are deteriorating reanimated bodies, I will assume they are slow zombies. Now you need to determine what is the game plan.