SAS: Zombie Assault TD is a tower defense game based on Ninja Kiwi's popular zombie shooter series, SAS: Zombie Assault. Your task is to prevent undead hordes from passing through each area with turrets, barricades, and SAS soldiers. You are allowed to completely block off the path to the exit, but if you do so, the zombies will attempt to smash through your defenses. You also have to be careful where you place your SAS soldiers as they are more vulnerable to zombie attacks.