Make no mistake, Long War 2 is not just about making XCOM 2 last longer, it makes it tough. Entry level missions have Sectoids and armoured drones with stun guns, and new ADVENT troops like the Engineer with her grenade launcher and the Sentry with her mad Overwatch skillz, and they all dodge like absolute bastards. Your hit rates are for shit and there's every chance that even a successful shot will be dodged for a minor graze. Oh, and there are a lot of them on each level, with a tendency to converge on you as soon as you go loud.
Now, it's not all doom and gloom. First, you begin the game with a few extra bits and bobs, in particular three grenade/utility slots, nanoweave vests - which provide 'protection' instead of extra health, which means that the first few damage levels don't count as wounds - and sweet, sweet flashbang grenades. Within the first mission I had come to love these little beauties, so much so that I felt betrayed the first time an ADVENT Engineer lobbed one back at me. On the other hand, regular frag grenades are much less reliable.
In addition, you begin with the ability to ship eight soldiers on the Skyranger, so you can send a hell of a lot of hurt out in a single package; the flipside is that you no longer land in the combat zone. The Skyranger drops off your squad and they infiltrate the AO, a process which takes several days, and longer the more people you send and the more heavily tooled up they are. Missions are time limited, and if you don't have time to fully infiltrate the already bastard hard opposition is increased. At low infiltration levels, the mission launch screen advises that the opposition is 'impregnable.' So, while you can send eight heavily armed bastards, unless you have plenty of time available, it may be better to send a leaner squad to face a reduced defence. As an additional factor, emergency extraction is not instant; it takes time for the Skyranger to fly in. Best not to hold out to the bitter end.
All in all, Long War 2 is a tougher, grittier version of XCOM 2, with more choices to make and much more of a feeling that you are scrabbling against the real power in the world. There's a whole extra level to the Strategic game as well, with Resistance Havens to manage and a sector control game I haven't even touched on yet on account of getting my arse kicked in the missions the whole time. Now, partly this is because I screwed up. The game assigns all of your squaddies from the first mission to a single squad - a pre-assigned group of soldiers that can be quickly selected in the load-out screen - and I didn't mix them up, so I have one unwieldy group of shitkickers and a bunch of frail and unsupported rookies instead of salting the veterans across the squads to support the newbies in leveling up. And partly it's because the game is brutal.