XCOM Base Defense (EU2012)

Mission Objectives

The invaders have infiltrated XCOM in unknown numbers. Limited reinforcements, including XCOM Base Security personnel, are available. Failure will mean the end of XCOM. Defend our base by all necessary means If all soldiers in the combat area are killed, XCOM HQ will fall

Source: XCOM: Enemy Within DLC

Notes

• This mission is always called: Operation Ashes and Temples.
• The Aliens can now attack the XCOM HQ once during a game, resulting on a Base Defense mission against the aliens.
• Base Defense always takes place 2-3 weeks after you've assaulted the Alien Base.
• While you're scanning for activity the Hologlobe on Mission Control will start to flicker and there will be a cinematic showing sections of the XCOM HQ exploding or being attacked by mind controlled XCOM personnel. Afterwards Bradford will inform you that alien intruders have been detected and you'll need to defend HQ's Delta Section.
• You'll start with some veteran soldiers and base security personnel (a.k.a. Blueshirts). Delta section has been cut off and you'll have to defend it from the aliens. The aliens will attack in waves.
  • The soldiers you get will always be the ones at the top of the list in the "view soldiers" area of the Barracks, which orders your soldiers first by rank, then by missions, then kills and finally arrival date.
  • Soldiers that are injured, on covert operations, in psionic testing, in the genetics lab or undergoing cybernetic augmentation at the time that the aliens strike are "unavailable" and will be passed over when the game selects your starting soldiers and reinforcement waves.
• If you lose the mission you'll lose the game.
  • You can restart the mission if you lose with a new RNG seed, this will work with Ironman enabled too.
• Your combat soldiers will be equipped with what they have at the moment in the Barracks and the base security will have Assault Rifles and Frag Grenades.
  • Keeping your highest ranked soldiers equipped is one of the most crucial things you can do to make this mission easier.
• You'll get 3 waves of reinforcements each time Bradford informs you that they've managed to reopen the security door.
  • Each time you receive reinforcements you'll get 1 of your combat soldiers, plus 0-2 Blueshirts.
  • You will only receive reinforcements in the second and third waves if you have taken combat losses, as the game will not allow you to have more than 8 active soldiers at once.
• The Blueshirts will have -1 HP and -10 Will than a Rookie.
  • If you get Tactical Rigging, the base security personnel will have 2 grenades instead of one.
  • Although Base Security personnel may earn promotions during the mission, you won't get to keep them as soldiers.
• Delta Section has a rectangular design, consisting of 4 linked sections: Rear Guard Station, Command Center, Mech Bay and Forward Access Tunnel.
• At the end of the mission Bradford will comment that "we still need to find how this was possible", although you'll need to play the Progeny campaign to learn about it.
• Depending on game progression, the Ethereal may be introduced in this mission

Tactics

• Expect to be fighting 30+ aliens during the whole mission. You'll face a mix of all types of aliens.
  • Naturally, composition will reflect current campaign progress.
• There are no penalties for demolishing the XCOM HQ, so feel free to use explosives.
• Blueshirts have terrible aim and damage with their conventional weapons, but their grenades are very helpful for softening up enemies and removing their cover so your soldiers can get good hits.
  • The Blueshirts operate best if placed on the higher ground where they can benefit from the appropriate bonuses, and can also benefit from Holotargeting. Consider using them to finish off enemies with only a few health points left, especially if your field operatives have much stronger weapons you'd rather save for overwatch or more healthy targets.
• Try to get a killing blow with a Blueshirt for the All Hands on Deck achievement, if you're playing to get them.
• Blueshirts don't last beyond the end of the mission, so feel free to use them as disposable scouts. You can absorb Overwatch fire with them, and try to get psionic enemies to waste their Mind Controls on them, at which point you can kill them. Try not to let Chryssalids zombify them though. If one of your soldiers is in trouble, you can move a Blueshirt out of cover to try to present a more tempting target.
• Falling dirt means that Aliens are about to drop in from the vents, so take a moment to look ahead and see if there's any falling dirt, as it'll give you a turn before they drop, as Bradford may not warn you until their turn.
• The first wave will drop directly in to the Command Center where your troops start, with some dropping in the Rear Guard Station and a few in the Mech Bay.
  • Try to get your soldiers on Overwatch on the elevated platforms in the Command Center for the bonus accuracy from high ground.
  • This is probably the most dangerous part of the mission. If you fail to take out the most dangerous aliens on the turn they drop in then they're almost guaranteed to get flanking shots or melee attacks in such an enclosed space.
• A large group of flying units will arrive at the Rear Guard Station. Most will fly in to the Command Center, but some may get "lost" and you'll have to go out and get them.
• After that more units will drop in to the Mech Bay.
  • Try to move some troops out early on to the elevated platforms overseeing the Mech Bay, you'll get excellent shots from the high ground.
  • If you're still fighting the flyers when the new wave drops in then you may be better off pressing in to the Rear Guard Station to buy time and then fighting the new enemies from across the Command Center.
• Two more waves of aliens will come through the Forward Access Tunnel. Bradford will urge you to go to them, but it's likely a better idea to keep your troops covering the Mech Bay, since it's very defensible. The aliens will eventually come to you.
  • It is possible to have reinforcements arriving at the blast door on the junction of the Mech Bay and Forward Access Tunnel if you advance your troops to that area, although the precise conditions are not known.

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  The Skyranger gets sabotaged

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  Bradford about to shoot a mind controlled XCOM technician

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  Command Center and Rear Guard Station

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  Mech Bay

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  Forward Access Tunnel