Zombieland/Drinking Game

The Zombieland drinking game. Drink whenever:
 * Survival rating: 20%
 * The word "Zombie" is said.
 * The word "Twinkie" is said.
 * A zombie dies.
 * One of Columbus' Rules appears onscreen.
 * You see a clown (a special amount is needed for this one)
 * A living character is introduced