SAS Zombie Assault 3 is an awesome free online game that can be played as a multiplayer game. It has just been through a massive update which included all kinds of new ranks, maps, guns and various skills. It's a great shooting/zombie survival tactic game that can be played in co op mode!
Press W,A,S,D keys to move around.
Click mouse to aim and click it to shoot.
Press G to throw grenades.
Press Q to change weapons.
Press R to reload.
Press F to fix baricade.
Press Spacebar To buy ammo.
You can choose between single player or co op.
Surviving levels levels you up adn gets you upgrades.
Yu have to kill as many zombies as you can and don't let em break down your walls.
Repare your defense wall.
Pick up health packs.
Stay in constant moving so you can repair and shoot at the same time simultaneously.
When playing in a team spread out.
The longer play the slower is your character.
Try go in circle around zombies with your team.
Spam turrets at the beginning of game.