Zombies have take over the world and now they are evolving. They can do whatever they like know and they are not mindless at all. You could live with them, but then again, they would want to eat you, so it would be best if you got rid of them. In this game, you need to shoot those biker zombies to be able to get to the next level. You would need to shoot those biker zombies as that would be the only way to get to the next level. Each kill would earn you money and you can use the money to buy better weapons.