Base Defence

Briefing

An Alien vessel has landed nearby. Our base is in severe danger. As per standard procedure all non-combat personnel and XCom craft have been evacuated. Alien units will enter the base via hangar doors or the access lift. Defend the base and its vital installations at all costs - this is a fight to the death.

Battleships

An inbound Battleship on a "Retaliation" mission means there is a high chance that a Base Defense mission is in the offing for you.

You can bring down these battleships with sufficient Base Defense Measures, but the game is programmed to just send another on the exact same mission. It's been proven that about 6 or 7 Fusion Ball Defenses with Grav Shield (total defensive strength 6000) can hold off incoming battleships (hull strength 3000) indefinitely, but since you get no bonus for blowing a battleship out of the sky, not even to monthly score, it's better to let them land eventually and just run the mission. Once you've run the mission, win or lose, the attacks stop coming. The aliens seem to forget where the base is...

BTW, only battleships actually assault your base, don't worry too much about other alien craft on "Retaliation" missions, they're just scouts. Shooting these down far away from your base may confuse the aliens as to where your base actually is.

Battle Tips

You really want everybody at home for a base defense mission. If you're caught with your Skyranger off at some UFO crash site, you'll have to defend the base with a rookie, two guys on crutches that were in med-bay, and the antique Tank/Cannon you hadn't got around to selling yet. Mind you, the odds are still in your favor.

Battleships will unload both regular aliens and their associated Terror Units. You won't ever see the battleship, but you will get to see all those nifty modules you've been constructing in the Base Planner view, close-up! Base modules have two levels. Soldiers will normally spawn/start in Living Quarters and Storage modules.

Base layout becomes quite important, as aliens can only come down into your base through hangars and the access lift. If you grouped your hangars with the access lift, then built one module only connecting to the access lift, that module becomes a choke point for base defense. A long chain of rooms becomes a long choke point ripe for mining with Proximity Grenades.

A soldier with a Motion Detector in an upstairs closet near the access lift combined with a rocket tank at standoff range will keep the aliens at bay until the rockets run out. -see also [Stewart's] strategy on xcomufo.com forums.

Blaster Bombs can clear your base in just a few turns, if you launch a few into the hangars and access lift. The problem is getting the program to supply your soldiers with blaster bombs before hitting the 80-item limit.

Hovertank/Launchers are almost as good at clearing out your base, except for the fact that their missiles are more prone to inaccuracy and often veer off and blow up against the wrong walls. Since the game has a "free ammo for HWP in base defence" bug, I don't see HOW you can lose as long as you keep 3-4 of these things in every base.

Corridors attaching to the right of a hangar come through a ground-level hangar door. Corridors attaching to the left don't get a door.

Doing too much damage to a room can also collapse it, and you will lose that room permanently. Any rooms that can only be accessed by going through the collapsed room will also be lost. Spawn-point rooms such as Living Quarters, Stores, Access Lift, and Hangars can't be collapsed.

You can recover lots of valuable Elerium-115 and alien weapons from a successful base defense. Losing or abandoning the battle means losing the base. Although sometimes you can still come out with a positive score for your trouble.

It might be best to disarm all your psi-weak soldiers at this base if there are ethereals or sectoids attacking.

[ NKF: Elerium collection from a base defence mission can only happen if elerium pods are generated in the battlescape. See, if you have 10 units in storage, the game will generate 10 pods in the base, given sufficient space in the object table. But because the way the game automatically converts 1 pod into 50 units at the end of the mission, you're basically getting 5000% more elerium from your own pods (those that don't get destroyed, anyway). None of them come from the aliens! Until this is verified for 1.4 and 1.4ce, it is safe to say that this will only happen in earlier versions of the game.]

[A somewhat unorthodox strategy, forced by necessity, paid off for Zombie: "I armed my best soldiers with the stun rods, hid them in the General Stores next to the Access Lift, and went to work. Every round a Snakeman would appear from the Access Lift, and every round one of my soldiers would stun the alien while another veteran grabbed the body and hauled the poor alien upstairs for observation. I was laughing so hard I almost peed my pants!" - as copied from strategycore. Mental picture of a Snakeman with a pillowcase over his head, zipcuffed arms behind his back, old army sock stuffed in the mouth, being heaved into a darkened storeroom on top of his buddies. "Right, that looks like the lot. $20K each, and a $1K cut for me, and $5K for Big Dave as a gift." --JellyfishGreen 08:34, 14 Oct 2005 (PDT) ]

To Surrender or Not To Surrender

There are only two costs incurred when you lose a base:

1. You lose the base and everything in it;
2. You lose points for the soldiers and tanks that died defending the base.

The loss of the base is presumably erased from the annals of history. It's all kept very hush-hush from the public. The non-combat staff and all ships that were at the base are disbanded and are not lost in the battle. X-Com ships vanish without a trace, probably stolen by wretched engineers. The deaths of the soldiers on the other hand are a lot harder to explain, and friends and families are bound to make inquiries.

Therefore, if you find yourself in a situation where you are defending a base against an enemy that you have no hope of winning against, should you surrender without a fight, or fight it out? You will need to base this on who you are fighting with and what you have to fight them with.

For example, a fresh batch of recruits in jumpsuits armed with regulation standard pistols and rifles against an elite squad of Ethereals and Sectopods. This can be classed as a hopeless battle should you not be able to utilise the weapons used by the attackers. In a situation like this, you should cut your losses and surrender without a fight. This will incur a 0 point penalty along with the loss of the base.

On the other hand, should it be against Floaters, you could push on and try your luck.

Alternately, you could also try to kill as many raiders as you can before surrendering. As long as you did not lose any soldiers in the process, you will get a positive score for losing the base. If this is an option, go for it. If not, don't.

It is understandable that some commanders may be too proud to go down without a fight. There is nothing wrong with that, but do try to consider the consequences of any actions before taking them.

Note: All of the above relates to raids on bases when you have more than one base. If you are put into a situation where you cannot save your very last base, then you should consider restarting the game.

Bugs

Base defenses can be DEADLY.

But not for the reason you think.

The game has some totally funky system for deciding what equipment in your base will be available during base defence. (See '80-item Limit' in Known Bugs.) So, if you've been accumulating a lot of clips or mission specific special equipment, you might have *problems*.

Ie, make sure to sell unnecessary stuff before base defences. (You don't want to be armed with unresearched "Alien Artifacts".)

Equipment assigned to your craft is not available for base defense missions, even if that craft is currently in it's hangar.

Also much feared is the dreaded "walled off section" or Base Disjoint Bug. Sections of your base along the extreme south and east edges will often be separated from each other by dirt walls. Heavy plasma and blaster launchers needed in this scenario to excavate the dirt. Possible that heavy explosives might work too, I'm not sure. Soldiers spawning in Stores or Living Quarters here may be trapped for the duration.

Another ANNOYING bug I find is the dissapearing bodies and booty from aliens. This is related to the 80 item bug problem.

A much nicer bug is that HWP's automatically get a free load of ammo (which is added to your stores if unused). Note you still need at least one soldier as aliens landing at an unguarded base - or a base defended only by HWP's - take it without a fight.

If you have a LOT of soldiers, enough to fill all your spawn points, soldiers will start taking alien spawn points. Which means less aliens. - much kudos to [Zombie]

Macho-ists: at superhuman, you get the same qty of aliens as in the battleship, eg +25 aliens, +8 terror units. to get the full compliment to attack you base, you need AT MINIMUM 2 hangers. (unless you want aliens to spawn in general stores downstairs corridor). Four hangers gaurantee maximum alien load if you use 15 soldiers and conservative loadouts. i usually defend with 10 guys, 2 tanks VS four hangers. LasR usually