SAS Zombie Assault TD is a TD Game developed and published by NinjaKiwi. Players need to protect civilians from zombies by placing various Defences in an open world-style map with no single path. The game follows the series' classic trend of using sentry guns and SAS soldiers to kill increasingly strong and deadly waves of zombies, which remain largely unchanged from the prequels. Air support is also available, but costs SAS$ to purchase, meaning it should be used sparingly.
The defences consist of barriers, SAS soldiers and sentry guns. Eventually, it will become necessary to use masses of Fragmentation Grenades to clear entire hordes of zombies to allow other defences to attack necessary targets, unless enough "mobbing" towers are placed, such as MGL Turrets or Flame Turrets.
All of the attackers are various zombies of different kinds. There are more advanced kinds as the game goes along. Smaller zombies generally get the advantage of greater numbers, while the Mamushka is highly frustrating due to its cluster ability, allowing it to swarm the map. The Ruin is the game's final boss.