Instructions
Shoot all zombies. Groups of zombies attack in rounds. Between rounds, you have 30 seconds to grab any power-ups and make any repairs without fear of a zombie attack.
Hold "X" in front of a broken window or wall to repair it. This will keep out the zombies for a time until it breaks again and needs another repair.
Approach writings on the wall and hold "X" to spend your acquired points to get new weapons and to unlock new map areas.
Run up to any dying teammate and hold "X" to revive him.
Repeat until your character dies. If you're playing multiplayer, the game ends when you and your teammates die.