So what's new?

The Expansions add a whole lot of new content for players to tackle. This include three new resistance factions that battle the aliens. Each of these factions function differently and control areas on the map. One must establish contact with them and perform quests in order to coordinate with the. Each faction will always have a nemesis that they will want you to hunt, though every game this nemesis will be different, chosen by RNGeesus. These nemeses are the titular Chosen, three hero aliens that also have a specialisation and evolve over the course of the game as more and more encounters happen. Their aim is not always to kill player units, but to capture them alive in order to interrogate them and gain strength.

The Chosen

• To the left, you have the Hunter. He hides and darts around the map using a grappling hook. He uses a powerful sniper rifle that he can use to fire a tracking shot in order to keep tabs on their target from wherever he is. Additionally he can use a special laser focused shot that grants the player one turn to evade the line of sight before this devastating blow is dealt. He also uses concussion grenades and tranquilizers in order to capture the player's soldiers.
• In the middle, there is the Warlock. He is a mad being that wields tremendous psionic power, but can also use an assault rifle if need be. These abilities include summoning undead spectral beings that will explode when in proximity to the player, or summoning powerful melee guards for protection. On top of this, he can also inflict enemies with madness, this can cause all sorts of mental status effects like panic, daze, or going berserk. Definitely a scary foe.
• And to the right, is the Assassin. She is a highly skilled enemy that sticks to the shadows. Thus she can become invisible and take the player by surprise with a powerful slash of her katana. This is her weapon of choice that she uses almost exclusively, but has a ranged weapon to use if the need arises.

Among these three formidable foes, the players will have their hands full trying to stay alive. Luckily they don't always go for the kill, but attempt to capture soldiers, as previously stated. Thus, rescue mission can be attempted. The player can chose to ignore them, but this will cause problems down the line, or they can take them out by assaulting their lairs. To help in this endeavour, the player can ally him/her-self with the three factions. However, diplomacy is key, as they don't like each other very much.

The Resistance Factions

• In the left corner, we have the Skirmisher. These soldiers are former Advent that have managed to escape indoctrination and have rebelled against their former alien masters. They come equipped with a bullpup submachine gun and a custom grappling hook. They can use the latter to scale buildings or grab an enemy, either to pull them in, or close the distance to attack from close range. Their might will be invaluable on the field.
• Holding center stage, there is the Reaper. They are excellent marksmen that can double as recon units. They always start off concealed, and can set of claymores attached to enemies with a silent shot. Each shot has a chance to reveal them, but if unlucky and their position becomes known, they have an ability, that can be used once per mission, that allows them to become hidden again. Their Dragunov-style sniper rifles are not only cool, but powerful, and surely a useful tool to take on covert missions.
• And finally, we have the Templar. Though they are trained in the use of automatic pistols, their main strength comes from the use of powerful psionic abilities. They can channel this energy to create a massive psi-blade, usable in melee combat. Every successful strike gives them focus that can be used to enhance basic abilities making them extremely potent in taking out full squads. They can also create a copy of themselves or unleash a powerful psionic storm to eliminate enemies in close proximity.

These new factions can provide recruits to use on the battlefield, but should be managed carefully on the strategic map. Speaking of, maps, new map pieces have been added to create more variety in the procedurally generated maps that the players will fight over. On top of that, a new type has been created to simulate the battered cities of the initial war the humans lost when the aliens invaded earth.

New enemy types

To deal with them, the aliens sent in Purifiers(pictured above). They flamethrower attacks affect a very large area causing lasting damage. Be careful when fighting them up close, as their gas canisters are highly volatile and could cause an explosion. Joining advent ranks is a new class, called the Priest. They wield an assault rifle, but their real power comes from psionic abilities. They can mind control enemies, and have a chance to evade death by shielding themselves. They can also mind merge with an ally giving them increased stats and health, however this is a double edged sword, as killing the priest will also take out the buffed warrior. And to top things off, there is also the Spectre, a humanoid enemy that is able to transform in an untargetable cloud at will in order to get in close for the kill. They can damage enemies while healing themselves and are able to render the player's soldiers unconscious while creating a copy of the struck target, thus creating an ally. Now that's an enemy to keep your distance from.

More customisation options and cool features

In this new expansion soldier can become good friends if they survive encounters together. This will boost their morale, and when on the same squad will grant them buffs and new abilities to use in tandem. This will be a great boos in combat, however, if one of them dies, then the other will go berserk and who knows what that will do to a carefully laid out plan of attack. After the mission they will also become mentally crippled, lowering their combat prowess in future missions.

They can be found in your base of operation's bar, having a drink or training together. They, or any soldier for that matter, can participate in photo sessions, in order to create propaganda posters. They can pose in all sorts of positions, ranging from the menacing to the hilarious. These posters will appear throughout the game, both inside your base and on the battlefield attempting to capture the hearts of undecided civilians. While this doesn't really affect gameplay it sure is a nice tough.

Other quality of life improvements include more fine tuning at the start of the game where players can choose longer timers, or doubling the health points of all units, making for more thoughtful battles and less insta-kills, among other things. Additionally, more icons ca appear on the battlefield to indicate whether an enemy will be flanked, or if they will flank you, or other informational aids. More customisation options are also added, especially once allying with one of the rebel factions, gaining access to their armour pieces and such.

Of course, more minor additions come with this expansions, such as more Dark Events to cause players grief, more mission types such as variations on the already existing ones, extraction missions, assault missions or defence missions, in which resistance guerilla fighters will also join the fray to aid XCOM in fighting the aliens. Under the hood, a whole slew of bugs have been squashed and game performance has been improved, as this was sorely needed. As I write this post, the expansion is downloading, and I can't wait to try the new features out for myself and, in future, see what the modding community comes up with. And if my rambling is not enough, below you have the official announcement trailer.