Orcs Must Die! Unchained is a free-to-play action puzzle game in the tower defense genre with a third-person view. Your task is to defend the fortress from the invading army of orcs using various traps. Along with the traditional Survival mode, the game includes a unique Sabotage mode. In this mode, two teams of three players compete on the same map, summoning enemies and bosses to thwart the enemy team.