Zombie shooters seem to be all the rage and one of the more recent ones just got a massive free content update. Steam owners of Nation Red, the top down shooter from developer DiezelPower, can now download the free update automatically.

The new update adds two new weapons, a number of new achievement, several new perks and the new Rage power up to the game. It also adds two new gameplay modes. One is called Barricade where you can use reloadable sentry guns to fight off waves of zombies. The other is called Auto Perk. This allows you to make a list of your favorite perks. When you play in Auto Perk mode the game automatically upgrades your character with your perks without having to have you pause the game to do so.