Procedural maps, randomised weapons and chain-smoking soldiers. In XCOM 2 [official site], the rules have changed. One seemingly minor addition to the tactical combat might have the greatest impact of all though. In our recent hands-on, we had a chance to test out the new concealment mechanic. It removes one of XCOM's few frustrations and creates an entirely new scouting phase as each mission begins.
Remember how the aliens always had the jump on you in XCOM? You'd stick to cover, make sure that none of your agents exposed themselves, and hope to get the drop on the bastards, and then scream at the monitor when one of those animations kicked in as soon as you sighted a gang of Ets. They scattered and scurried for cover, again and again, until you accepted that they'd probably seen the Skyranger coming, and that your sneaky tactics were all for naught.
That's no longer the case.
In keeping with XCOM's new role as a hidden organisation, trying to bring down the alien authorities from the shadows, your squads can now take advantage of cover to conceal themselves, as well as to hide behind once spotted. The new mechanic that allows for stealthy approaches and planning goes by the name Concealment and it's a perfect example of Firaxis' careful marriage of systems and themes.
Your squads would be fairly terrible clandestine agents if the aliens always knew they were in the area. To reflect the guerrilla warfare campaign that you're waging, while addressing that stolen march that was a cause of such frustration in the first game, your squad members are concealed at the beginning of each mission.
That means you can move everyone into position, placing snipers on roofs to provide coverage and setting up ambushes for patrolling aliens. As long as you're not spotted and don't make too much noise (firing a gun, for example), you'll be able to scout out the area and get a bead on enemy positions and movements.
When you fire your first shot, any XCOM operatives with line of sight on aliens or Advent soldiers will fire in sequence. That gives you the ability to take down an entire enemy squad in one action but the tactical advantage is a slight thing in comparison to the power that the earlier reconnaissance provides. Being able to see enemy movements before they're aware of your presence not only gives an insight into the way they patrol and guard locations, it also ensures that you feel a sense of control over the battlefield than was the case in Enemy Unknown.
The scouting works in combination with the procedural maps. The sense of the unknown that they provide, the fact that the precise layout can never be known in advance, means that retaining concealed status for as long as possible can be very advantageous. Even a brief session with the game demonstrated the importance of scoping out as much terrain as possible, and that's at odds with the first XCOM, in which missions usually entailed creeping from one encounter to the next.
Here, it's entirely possible to avoid encounters until finding the one that works best as your first point of contact in any given situation. Effectively, you're picking your point of insertion and angle of attack, rather than sticking to the path laid out by a level designer.
I'd thought that concealment might not be effective unless the setup of a mission were crafted to support it, or that it'd feel like a special ability to be utilised when conditions are ideal. Now that I've played the game, I don't think that's the case at all. Concealment and the stealthy approach are a key part of the redesigned tactical layer of XCOM 2 and are central to the way that the mechanics fit with the theme of resistance and retaliation.
If concealment had been restricted to a specific class, it would have been rarely used, or one of those apparently optional skills that turn out to be an essential component of victory. As it is, Firaxis have made it a cornerstone of their sequel and it's one more way in which XCOM 2 has been fundamentally altered rather than simply expanded.