In the old western part of the America, everything is settled with a gun. Though, there are sheriffs that time that acts like a cop, they are only few and you could guess that they won't be able to cover lots of ground. Sometime, the sheriffs are killed. That is why, it is called as the Wild West. This game is made from that idea. You need to kill the bandits or they would kill you since you are the sheriff around there. You need to act and shoot fast or you might end up dead. Hence, the term be quick or be dead is applicable here.