The worlds is at war and you have fight your way through every continent to survive. Start with just a pistol and march through the first continent of your choice. Along the way you will be able to use military vehicles to your advantage. Keep surviving and you will unlock cool weapons like AK-47, Bazooka, and grenades.
Use the AWSD keys to move. Use the mouse to aim and shoot. Use the E key to get in and out of vehicles.