After beating XCOM 2 on Ironman, an incredible feat considering the technical issues I encountered along the way, I wanted to share with everyone some advanced tactics for keeping your soldiers alive and doing the most damage to the aliens. Some of these require the situation to be just right, but if you find yourself in a position to use them, they can turn the tide in your favor.
1. Use the Battle Scanner on retaliation missions.
The battle scanner is perhaps one of most under-appreciated items in XCOM 2. You can unlock it nearly from the start and it can provide some excellent vision to help you plan ambushes.
One very special feature of the battle scanner is that it detects Faceless among civilians; therefore, make sure someone has one on every retaliation mission. You do not want your ranger to jump into close range of a civilian only for it to become a Faceless. Play it safe; throw the battle scanner into a group of civilians as soon as possible in the mission. You can also use the Specialist’s Scanning Protocol for the same effect.
2. Overwatch can be devastating on melee enemies.
Certain enemies in the game, such as the Stun Lancer, vastly prefer using melee attacks. This means that they will dash toward one of your soldiers during their turns. Use this to your advantage. Rather than taking a shot at them in full cover, go on Overwatch. Then when they dash to attack you, you will get a better shot on them. This is especially useful if you have upgraded your specialists’ Overwatch aim at the Guerrilla Tactics School.
3. Keep your Psi Operatives out of the enemies’ line of sight.
Several of the abilities of the Psi Operative do not require line of sight. Use this to your advantage by avoiding moving your operative into a position where he or she may be fired upon. It may be tempting to use the operative’s rifle to add to your firepower, but one hit and they will lose valuable training days from being wounded. Use your non-line-of-sight abilities, and only move them into firing range once you have the situation under control.
4. Killzone is amazing, especially with a Sharpshooter on elevated ground.
Killzone is probably my favorite ability in the game as it allows the Sharpshooter to take Overwatch shots against all enemies in a cone. This is especially devastating when you set it up before activating a pod. The aliens will scatter and all take a shot. Killzone works best when the sniper is on high ground to counteract the Overwatch aim penalty (although they do not get this penalty when firing from concealment).
5. Use Serial with a Specialist or Sharpshooter when facing cloned Codices.
When Codices take shots, if they are not killed they will clone themselves. This can be pretty devastating if they are allowed to go into their next turn with multiple active Codices. Note, however, that when a Codex clones itself, it splits its HP between itself and the clone. This usually means both enemies have low HP.
Save a Specialist or Sharpshooter with the Serial ability for after you take a shot on a Codex. Activate Serial and you should be able to, as long as you hit, kill all the low health Codex clones in one move. I found this exceedingly useful, especially in the final mission.
6. Don’t risk going for controlling turrets with Haywire.
Generally, I found that when I controlled an enemy turret it simply did not do much against the other aliens. It has a fairly low percentage chance to hit most alien types in any situation. Why risk failing the hack? Just go for the shutdown on the turrets so you don’t have to worry about them.
7. Use Spider and Wraith suits with your Sharpshooters.
Sharpshooters are far better from high ground, and the grappling hook ability available on both Spider and Wraith suits costs no actions and gets them to the high ground. You can even get to high ground that is inaccessible via climbing or other means. This is very useful if you want to take a shot but you aren’t in a great position. This is the only way you can move before firing the sniper rifle.
8. Reaper is a fantastic followup to grenades, but give your Ranger the Hazmat vest.
Reaper is a great way to finish off a group of enemies with low health, and area of effect abilities like grenades can be a great way to create this opportunity. However, you need to be aware of the fact that almost all grenades will create some kind of environmental hazard in the area. This can damage your Ranger as he or she is using Reaper unless you equipped the Hazmat vest, which is created at random from the Proving Ground experimental armor project.
Note: I am aware that as of the current version the Hazmat vest is not protecting from acid. I am expecting that this will be patched in the future.
9. Try to position your squad so a Grenadier with Holo Targeting shoots first in ambushes and other times the squad is in Overwatch.
Holo Targeting is pretty useful when used correctly. In Overwatch, it can counter the aim penalty for the rest of the squad. To use it most effectively, you may want to position your Grenadier closest to where the enemy will be. This may mean leading with the Grenadier when moving in concealment or or breaking concealment by firing with the Grenadier so the rest of the squad’s Overwatch shots are more likely to hit. This is especially useful with high HP enemies like Sectopods.
10. Throw Mimic Beacons into cover. [Note: as of the most recent patch, this is no longer true. Mimic Beacons no longer receive cover bonuses]
Contrary to what the item description suggests, decoys have health and can be killed. If the aliens kill your beacon, then it isn’t protecting you anymore. To help avoid this, throw your beacon into a position closer to the enemies but still in cover. This makes it more likely for the enemies to miss the beacon, thus allowing it to distract other aliens on the field. The longer it can survive the better.