Sink into the crazy world of zombies and weapons. As you have already understood, your main task is to kill them and stay alive as long as possible. Be sure that you can cope with it. Upgrade him and survive at any rate. Just have much fun.
Just imagine that you are a police officer surrounded by deadly brain eating zombies. Are you scared? Then just try to use your police car as a cover. You will have to shoot them down as they approach. Try to stay safe and survive. Do not forget to collect as much coins as possible and earn achievements, just collect coins and purchase new weapons and abilities. Everything depends on your skills, then main things is to upgrade your hero and help him to clean the city from these terrible creatures. Have fun!