There are many types of deadly enemies in XCOM 2, but among the deadliest are Sectopods and Gatekeepers.
I used to be pretty afraid of Sectopods, until I discovered how many different items and abilities can completely wreck them:
- EMP grenades/bombs bypass their thick armor, and do massive damage. They also have a chance to shutdown the Sectopod (for up to 2 turns?), and decrease its resistance to hacking (for 1 turn?).
- Similarly, Blue Screen rounds can do massive damage to a Sectopod and lower its hacking resistance, though I think the round damage is mitigated somewhat by armor, unlike the EMP grenade. However, equipping the rounds on a grenadier with the shredder ability can get around this limitation very easily.
- Combat hacker specialists can temporarily shutdown or take control of a Sectopod with their Haywire Protocol (made easier if a teammate first lowers hacking resistance with EMP grenades or Blue Screen rounds), or they can do massive damage with Capacitor Discharge, which acts like an EMP grenade. Additionally, with a fully upgraded Gremlin III, the Combat Protocol ability does a fair amount of damage (I think it was around 10-12) that bypasses armor (I think).
So, with all these different weaknesses, Sectopods aren't so scary for me to deal with anymore, especially if I shut them down for 2 turns with an EMP or Haywire Protocol.
My question is, do Gatekeepers also have any special weaknesses to certain items or abilities? They're very heavily armored, so of course bringing along a shredder grenadier and/or an Acid Bomb helps strip the armor off.
However, unlike the Sectopod, Gatekeepers can't be disabled for a few turns while you whittle them down, which leaves your squad vulnerable to its super deadly laser beam or AOE psi attacks. You could stall a Gatekeeper with a psi soldier stasis bubble for a turn, but that also renders the Gatekeeper immune to attacks for that turn.