Escape all zombies you meet on the street and the ones, that chase you. Ride your scooter and collect various boxes with bonuses inside. Use your gun to kill zombies behind you and speed up!
Don't you think, that you can deal with the hordes of zombies ahead? Even if you had a powerful weapon, you still won't have enough bullets to kill all zombies, that come to have a bite of your flesh. Escape this street and find some place to hide. Use a gun to stop zombies, that chase you and collect bonuses to temporary increase your power.