Wall
Walls provide basic damage protection against Enemies. They are used to protect fragile targets from advancing enemy forces, and extend the amount of time defensive structures like turrets have to kill the enemy.
While walls block movement for both the player and enemies, Gates can be constructed to allow easy automatic passage for the player. Gates share the same health and resistances to walls, so no defensive power is lost.
Walls do not block projectiles, however, allowing both the player and enemies to shoot over the walls at nearby targets. Ensure that all walls built are far enough away from precious machines so they cannot be damaged over the walls. Due to projectiles' ability to fly over walls, turrets built behind walls will be able to shoot at enemies. This is optimal, as it allows turrets to avoid damage from melee fighters, which must break through the wall to attack targets behind it.
Due to the resistance of stone walls, they can take a long amount of time to destroy, despite having less health than most defensive structures. However, it may be necessary in some cases to double-layer walls, to slow down enemies even more.