What tactics to use for final fight?
Disclaimer: I've already completed the game, so I know what to expect in the final mission.
That said, the fight right at the end was (almost) a complete balls-up. I managed to
kill the first 2 avatars, but then I got pinned down in the open area after the bridge by the constant waves of reinforcements. In the end I took the last avatar down after exhausting all my grenades and with everyone in the squad wounded.
And that was just on Rookie.
So, I'm wondering what the best approach is for that fight, for my second playthrough on Veteran. Should I charge in and try to eliminate each boss as fast as possible, or draw them out on to the bridge? What squad composition would people recommend?
Solution 1:
I'd recommend waiting on the side of the bridge opposite where the avatars and enemies spawn. I think that charging in is suicide, you're just asking to get flanked.
Send someone with high movement forward to trigger the avatars and waves of enemies, then run them back. There should be enough cover on your side of the bridge to just set up overwatch and destroy anything that pops into view. I'd recommend using mind control from your Avatar on any organic enemies, use these for scouting and early damage. I brought along 2 psi soldiers which made things quite easy as I just dominated an Archon and a Andromedon. Calling in Blazing Pylons every other turn as well as being able to launch acid is very useful against groups of enemies, and with this setup I had 9 soldiers able to overwatch and fire every turn, which made short work of any enemies. As another tip, try not to use any consumables before getting to this portion of the mission.
The squad I used on commander to win without injury was: 2 psi operatives 2 grenadiers 1 rapid fire ranger 1 gunslinger sniper
Another fun idea: I believe you can dominate a gatekeeper and use it's "raise zombie army" ability, which would make that last mission quite fun.
Solution 2:
I managed to make in on commander difficulty using 2 snipers, 1 psi, 1 grenadier, 1 ranger, 1 support and the avatar. I had suffered 0 injuries and used only 1 fire grenade (the fight was fairly easy so I thought there will be another ultimate boss or something -> as a result I preserved them for nothing :)) ).
The trick was to use wraith armor on snipers. This way you can grapple on to a normally inaccessible area just after the bridge (one on the left, one on the right).
Strategy: 0. Rule number 1: Don't charge in. Position your squad as effective as possible and cover as much ground as you can (avatar teleports after being hit).
Recharge all your powers before crossing the bridge (especially aoe from psi and avatar)
I went 3 left 4 right.
Mind controlled 1 unit with the avatar (doesn't really matter which, you just need the vision, just take one that doesn't die fast).
Mind controlled a second unit with the psi (same note as before).
Killed the 3rd unit and shot the avatar (took about half of his hp).
Used aid on an the ally closest to the avatar. When he moved he got shot and lost his turn (you always need to do that or he hits like a truck).
Mutons spawn on right platform, used a void rift and sniper serial to kill them all.
Focused and killed the avatar.
Put all that remained into overwatch.
Sectoids spawned on left platform, killed them with a grenade.
Avatar spawned and some andromedons on far left platform.
Killed avatar with the snipers + 1 overwatch hit (after I ended turn). Ignored rest because they were far.
Last avatar spawned, died from 2 crits of the snipers and 1 slash from the ranger.
Congratulated myself.
Somewhere in between those steps I also used the void rift from the avatar and a null lance to take some snakes down (but can't remember when so I did not include it in steps :) ).
Snipers did most of the work (and I was glad because they were useless on the rest of the mission, since they had no high ground and shitty angles).
I think that without the wraith armor it would have been pretty hard.
Solution 3:
The best strategy would be, as described by many, a blitzkrieg against Avatars, since when they die it's all over. However I will tell you the other approach to this battle, for the case when you can't do it the easy way
I've had this fight last 15 turns from the moment I engaged the first Avatar because the second Avatar bugged out and teleported to the other end of the map, and I realised it only after a while and didn't send anyone to find it. This forced me to kill over 80 aliens before the last Avatar run in from the back of the hall, and here is my recipe to doing it:
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Mind control is your friend, but correct usage of mind control makes the fight so much easier:
- Most aliens attack are weak and unreliable compared to your soldiers. Thus, use them for defence and utility. Codex's disarming, Viper's pulling are so much more useful than just some Berserker or an archon.
- Aliens prefer shooting at the easiest to hit target. They don't care that Gatekeeper is armored, as long as it's exposed and next to them, they will shoot at it instead of taking pot-shots at humans, even if said humans aren't in cover.
- Avatar's mind control is unlimited uses but limited duration. Make sure that its target perishes from enemy fire before you lose control, but not too soon.
You need to be killing an average of 3-6 aliens per turn, or get overrun. Sometimes a sacrifice or a risky move should be made, if you are in danger of not getting enough aliens this turn and the next.
- Anything that gives you more shots — Serial, Death from above, additional Overwatch from support drones, — makes achieving the above target easier. Any move that does not take result in an alien shot has to be avoided.
- Be constantly on the move. Most cover is easily flanked, and most cover has opposing cover, so staying in one place is inviting disaster.
- Try to keep enemies clustered. Instead of spreading and taking on all enemy packs at once, hunt them down one by one. It's better to skip some of the tougher packs and ignore them till the Rift recharges and you can take them out all at once, then to take down two on the left, two on the right, and have at least one of your flanks in grave danger on the next turn.
Solution 4:
It seems like defensive approach is just plain wrong since enemy have infinite reinforcements here. So the key factor is speed. Kill first avatar in the first turn, second - in the second turn and you have two or three turns left to hunt down that last bastard who have ill tendency to hide somewhere in some far corner of that large hall. I've got an assault character who killed first and third avatar. This assault had fully upgraded flanking attack (~15 HP per shot + Rapid Fire perk) and AP rounds. Also, this assault had superior speed PCS and sometimes got help from PSI Op with his "Inspire" ability, so she could dash from corner to corner, make a flanking attack, and retreat behind suitable cover ("Implacable" perk). Second avatar was the most difficult, as it managed to mind-control my assault mentioned above. So my soldiers had to shot it three or four times. Occasionally it was executed, as one of my soldiers had "Superior Repeater" upgrade, so some amount of luck was involved. Because avatars have tendency to teleport, my soldiers were scattered to three hunt groups across the hall and had mind-controlled Andromedon by my PSI and mind-controlled Gatekeeper by my Commander to make these small groups somewhat stronger. After all, this fight was flawless or almost flawless. It involved some luck, however.