Concealment (XCOM2)

Concealment is a new mechanic introduced in XCOM 2. In certain mission types your squads will start concealed, which means that the enemy wont be aware of your presence, and will patrol the map without knowing precisely where you are. The best about this new mechanic is the possibility of setting ambushes. To set an ambush just distribute all your soldiers in good cover and put all except one in Overwatch, then use the last soldier to attack, this will break concealment and hell will break loose-- though be aware that any survivors may then be primed to counter-attack.

It is effectively impossible to full stealth a mission, as either you will need to clear the area of enemies, or the site of an objective will be camped by an alien pod: even if you get close, doing the required action will reveal you. The only Concealment-centric Achievement is to simply set up an ambush.

Normally, the area shown around a patrolling pod is roughly the movement range: remaining outside this range will usually ensure that you won't be spotted in the next movement. However, one Dark Event, Vigilance, increases the LoS/Alertness radius of enemies while in concealment mode (but won't increase movement range).

Breaking Concealment

As said before, attacking will break concealment, but that is not the only thing that will break it. Stepping into an enemy or civilian LoS will break concealment too, also failing a hack attempt or a patrolling enemy flanking you will reveal your squad: they will also get a free shot on the flanked soldier. Also, running through windows or doors breaks concealment; but if you take cover next to a door first, you're allowed to open it without breaking cover.

Getting most of Concealment

There are certain skills that can be used to boost the effectiveness of Concealment. Rangers excel with Concealment, their first three Scout skills allow it to remain in concealment, get an aim and critical chance bonus when in concealment and also enter Concealment again once per mission, you will be able to flank, attack and most probably kill an enemy in the same turn.

Sharpshooter´s Kill Zone and Grenadier¨s Saturation Fire will get most out of this game mechanic, since enemies will be out of cover so you will have the bonus to Aim and Crit with each shot when attacking with those AoE skills.