You've driven the aliens back, stolen their technology, hacked their mechs and autopsied them, but you've yet to wear their skin into battle. This oversight is fixed by the new Alien Hunters DLC, which adds a story mission, three new boss monsters and three new pieces of elite armour, which all bear a slightly horrifying resemblance to the boss creature they came from. Unsurprisingly, the very sight of this armour freaks out the alien race you happen to be mimicking. You don't see XCOM 2's vipers wearing mens' faces for hats. In this respect, humanity may have gone too far this time.
The DLC seamlessly integrates into your campaign, picking up the trail of XCOM 1's Dr. Vahlen in a decent new mission with a fresh tileset. Without spoiling too much, science has gone wrong again, and now three 'ruler' aliens are on the loose. They will invade your missions randomly until they're dead, or you are. Their huge healthbars and tendency to teleport out make them tough to catch, but that's the idea of Alien Hunters. The aliens aren't just a threat anymore, they're sport to be hunted, skinned and worn. A new room in the Avenger even mounts heads of captured aliens on the wall.
I haven't had a chance to see how the bosses operate in a live campaign environment, but thanks to some Firaxis savegames I've had a chance to fight them. I won't spoil what they can do, because that nasty element of surprise is part of the fun, but they're both tough and very fast. Instead of waiting for your entire team to move before taking another action, they move between each soldier's movement. That means they can do a lot of damage in a single turn, and can portal away in moments.
Movement restriction abilities are useful, then, along with high-damage weapons. The DLC happens to add both in the form of new prototype weapons and a frost grenade that can freeze an enemy still for a few turns. Prototypes are hard to come by, and are be lost in battle if you fail to recover them.
The guns are worth the risk. In contrast to the high-tech weaponry your scientists produce, they look ornate and antiquated. The bolt caster does huge damage but must be reloaded after every shot. The new handcannon boasts a polished wooden casing and grip, and comes with an ability that puts your soldier into concealment if they land a killing pistol blow.
The new items are nice prizes, and the new bosses ought to provide a interesting disruptive element to your campaign, but they won't necessarily encourage you to play differently. Weapons such as the Shadowcannon pistol synergise nicely with the sharpshooter's gunslinger skill track without changing too much about the class. The bosses have some new abilities and behaviours, but are exaggerated versions of enemies regular players will be familiar with by now.
Alien Hunters is on the right track, however, and it shows how tricky it is to expand XCOM 2. New scripted missions are only interesting once, and new gadgets and enemies alone don't necessarily make launching a new campaign worthwhile. I'm more excited about XCOM 2's next piece of DLC: Shen's Last Gift. That adds a new class with “unique upgradeable weapons, armour and customisation features” and is due out this summer. I'd be more tempted to wait, install both DLC packs and then start anew with a richer suite of new toys to play with.