Survive the night fighting off zombies from your barricade. Survive longer than a day by making use of the daylight hours effectively by repairing your barricade, searching for weapons and looking for other survivors to help repair and defend.
Kill all zombies before they reach the top of the canyon and wreak havoc on the citizens of Zombville. Kill them all, make money, upgrade your weapon and buy power-ups. Good luck!
It's a nightmare. You are trapped in an abandoned mine with an injured comrade at your side against God-knows-what. Make your stand, get out alive. Three words of advice: shoot to kill. These things are not human, they are monsters..
Zombies have attacked and mankind has been devastated. Every day is a battle in the war to survive. Few remain to hold them off. Shoot those zombies and save the world.