Walls are tech 1 defense structures. They can be used two ways: To hinder movement of your opponent's army, or to block your opponent's fire. Their high health, miniscule expense, and small individual size makes them ideal as separators between defense turrets to prevent one bomb from damaging another turret etc.
Blocking enemy fire Edit
In reality, walls are too low to block 99% of weapon fire, and cannot be counted on for this task. If you need protection, you should consider shields or tactical missile defense. The only time a wall can be used semi-reliably to protect anything, is when they are built directly adjacent to a tech 1 point defense unit, but protection will still be minimal.
Hindering enemy movement Edit
This is the core function of the wall. Don't expect it to hold for long though. The idea is to use the wall for one of two strategic advantages: 'funnelling' larger troop formations through small spaces in a large wall with a larger defensive force on one side of the wall, or preventing short-range units from closing in on longer range units. Often these strategies are used in tandem with point defense or with area of effect weaponry such as artillery. A wall's bottleneck will maximize artillery AOE damage by forcing the clustering of enemy units whilst ALSO preventing shorter range units from being able to engage the longer range artillery. Cybran T1 mobile artillery and T3 Loyalists are notorious in a wall-bottleneck scenario, as their EMP effect will cause enemy units to actually contribute to the bottleneck, further hampering their attempt to cross the wall.
Walls are also sometimes used in conjunction with shields. Shields provide good defense against fire unless enemy units get within its radius; a line of wall segments can be built following the curve of the shield to prevent enemies getting too close. This tactic works very well because then no units can easily get inside the shields and defeat the generator. However, this can be defeated by T3 mobile heavy artillery.
Destroying walls Edit
One of the things that render walls tougher than they are is that units do not fire at them by default. This means that to destroy a wall, the player must manually tell the unit to destroy each and every wall segment, requiring the player to invest attention to the wall. Furthermore, walls have a massive amount of health (4000, per segment), so you are usually better off finding another way around the wall than through direct fire. Even if you destroy just 1 segment, the hole will still be too small for maneuvering an army.
Since walls are cheap, the most effective way to destroy one is to reclaim it. An engineer, SCU or ACU can reclaim a wall. Also, a very few combat units like the Harbinger have an engineering suite that allows them to reclaim walls. Once the unit is in range, the reclamation is nearly instant. If carefully micromanaged, a group of such units can punch a hole in a wall very quickly.
Building walls Edit
At 10 energy and 2 mass, walls are the cheapest unit, the cheapest anything in the game. They take 10 game clock units to build, so a tech 1 engineer can build one in 1 second, whereas an ACU, even with no engineering upgrades, can build 4 walls per second. Because of this, building a 3 layer sized walls is still a fast and inexpensive operation, and pretty much prevents the enemy from getting through unless they have air transport. This aspect is both a godsend and a curse : while they can be built quickly and cheaply, enemy engineers can reclaim them just as fast (faster in reality, due to construction overhead of targeting, not required with reclaiming) ! One tactic is to build several columns of walls together, but leave gaps in the columns every few walls to fill with AA, shield generators and point defence, or even one large gap to allow your units to pass through or to force enemy units into a nice, cozy space to be arty'd the crap out of. Anti-missile systems behind the walls increase the defensive capability further, until you get an impregnable wall of forticfications only an experimental unit can get through. This works especially well with the UEF, as they have the only Tech 3 point defense.
Sneaky Strategy Edit
Occasionally, if your opponent doesn't scout, you can fool them into thinking that there is a walled point defense structure in a position that he hasn't scouted yet but has radar coverage for. This is because any unidentified land structure appears the same to radar. The reason this can work is because the nine-block pattern of a walled point defense is easily recognizable, and therefore possible to fake for minimal protection. However, these fake point defenses will likely result in your opponent bringing artillery to bear on the position, so don't expect it to hold for long. It is more of a deception and distraction tactic than anything.
Doing this multiple times on the same map might also lure your opponent units onto real point defenses, only to realize too late that this one was real.
Walls don't provide any form of intel whatsoever. Walls cannot tell you that there are units nearby, if they have been breached, if they are being attacked, how much health they have, or even if they have been destroyed. You will actually have to scout your own walls to know its condition. Ideally, you would do this in the first place, though, through radar and wall-mounted turrets
Walls are very useful against the small t1 units, and any units with beam weapons, like the Rhino.
Walls do not count towards the unit limit. (This may be incorrect. Wall counted a 1/10 of a unit in campaign mode)
Some non-massive units can walk over walls. These include:
- The Cybran Salem Class : T2 Destroyer
- The Fatboy (all other land experimentals are massive)
Factional differences Edit
While all the faction's walls look different, the stats of the walls are perfectly alike, except for the cybran, which is a bit shorter, and the UEF and seraphim variations being slightly taller. This applies only visually, the increased height does not create more protection. Only the UEF and Seraphim walls have nicknames: Calcicrete and Haas.