Shoot the incoming enemies to protect your base. Collect weapons and turrets that automatically fire on the incoming missiles. Push the turrets around the battlefield to take advantage of their range and abilities.
Take to the air in the meanest Helicopter brawl around. Deliver your own patented brand of Justice to the criminals whom have invaded the skies of your fair city.
Zombie lunatics are attacking the city in broad daylight! Grab your SWAT weapons and let's grind some zombies into ground meat. You must protect the city, and above all, the president!