First thing to strike me:
No iron man mode, wtf? However, looking back, that was a later addition to the last game as well. I'm sure this and the various other tweaks (most of which I ticked on) that were added to the last one will be added in at some point.
Among them, the randomizing of rookies, presently, all rookies share the exact same stats. It is what it is.
The story...well, I've watched enough Outer Limits to wonder if there isn't a massive twist coming.
Caveat: I'm playing on sissy normal, because I didn't want to have to play to win, but rather play to try out as much stuff as I could whether it was the 'best' option or not. It's too easy for my skill level, and I recognize that.
I also haven't felt the need to expand my squad size past the initial 4 as a result.
The Economy:
The economy breaks down into Supplies and Intel.
And right now, it feels really unbalanced.
I'm always scraping for supply, and leaking intel out every orifice. Your monthly supply comes from the number of territories you have resistance cells in, and it costs Intel to gain more territories. However, you need to build comm equipment on your UFO to hold more territories, and that equipment needs power, so you need more power couplings as well, both of which cost supply. Lots of supply. You can also build radio beacons in territories that increase a countries supply (and decreases the intel cost of close by territories), but it costs supply as well, and takes 2 months (on average) to get your investment's worth.
There is a black market (now a physical location) where you can buy items with intel. However, it's most efficient straight up buy ~100 supply for 30 intel is limited to once a month. You can roundabout buy an upgrade for intel and sell it back for supply as well, or sell data caches of intel for funds, but both are far less efficient than the straight up supply exchange.
There are also bonuses to having a resistance cell in every region of a continent. Right now, none of the ones I have help the economy, but I haven't really looked into other continental bonuses.
Curiously, spending time at your home base, you can generate intel, but not supply.
It's come to a point where I determine which missions I go on based on how much supply they give me, not which evil event I'm going to stop.
scientists and engineersAs with above, the research/production section of the game feels a little off balanced as well.
I presently have 1 laboratory with 2 scientists. I have 4 engineers, 2 of them working in a workshop (which gives you 2 engineer robots for each engineer in the workshop), so I effectively have 6 engineers. AND I NEED MORE ENGINEERS, not scientists.
Scientists (at least so far) can research in the lab. You already have a default research rate. 1 scientists = 33% reduction in time. The second scientist? additional 17%. If that diminished return keeps going, my third scientist is only going to add another 9%, and a fully staffed second lab's fourth scientist only 5%.
Meanwhile, my engineers are needed to staff everything else on the ship. Have to staff the power couplings with engineer, the med bay, production, practical research on the theoretical research the scientists did, communications, salvaging ship areas, building new rooms. (Caveat, there are bonuses for building certain room types on certain areas, I just barely noticed the popup on that, don't think there was good documentation, so I've probably built the place all wrong and could have saved some staffing)
As it is, I bought a scientist early (for supply, damnit) and whish I hadn't. Should have just waited for the next rescue mission and bought another engineer. Not really a problem, just curious. Why can't a scientist staff the med bay? (not it's real name, but that's the function)
Unfortunately, producing things to sell at black market is inefficient. (at least what I can produce so far)
Some of that is due to most production now uses up corpses. (which is...really disgusting) And I don't know what corpses are going to be valuable yet as a result. Now that you're not shooting down UFOs, you need to rip the armor off the dead to put it to use. This is also thematically odd for the story when you think about it, your missions are mostly 'get in and get out' guerilla tactics, sneak and small engagement. But make sure you take the time to drag all the corpses with you. Just don't think about it too hard and roll with it.
ConcealmentThis is a big focus...and yet it's not.
Many missions, you start hidden and are free to sneak by enemies and set up ambushes. In the right circumstance, it's a riot to devastate hoards and pay them back for all the traps you fell into in older Xcoms. In reality, you need to just wipe out the first patrol you see ASAP with it. Be advised, breaking concealment initiates the double move from the last xcom on the alien's part. They see you (hopefully you just tossed a grenade into them or sniped the biggest threat), and they get a free dash to cover. Concealment allows you to get reaction shots in as they head for cover. However, it's often better to just not set up overwatch, let them scatter, then perform your normal moves.
Once concealment is broken, any enemy that sees you gets their free cover dash, which can be either advantageous to you or not. If they move into visibility on their turn, see you, their free dash ends their turn.
The Missions:
Mission type 1: Go destroy/hack/recover item. Time limit 8 turns, timer stops when you get the thing. Begin concealed, free to sneak up and set an ambush.
Of these, I like the destroy option best. A couple grenades in a building and the timer is done with. Generally takes 2-3 turns just to reach the object, and that's if you don't run into patrols (unlikely). There is an upgrade in the guerilla tactics room that allows additional movement while you're concealed that will make the timer much more manageable.
Mission type 2: Rescue/escort person. Time limit 12 turns, no stopping, must reach an evac point. Begin concealed, free to sneak and set ambushes. *ANYONE THAT DOES NOT EVAC IN TIME IS LOST*
Turn timer is ROUGH on these. Again the guerilla tactics upgrade is useful, so are some of the armors that increase movement options to an extent (you can't armor your VIP). Protip: While normally dashing immediately ends your turn and you can't take an action after, you CAN evac after a dash.
Mission type 3: "Retaliation". The new terror mission. No concealment, no time limit, kill everything, rescue civilians.
Classic feel, love these. Once a month. Ish.
Mission type 4: Base attack. Start concealed, no time limit. Plant device and evac.
Finally a time for the concealment to shine.
I'm sure there are a few more types for special circumstances. I know one dark event is interceptors hunting your ship down, so presumably a base defense situation.
The Classes:
Sharpshooter: Sniper, yay...but sniping doesn't really fit with those timer limits...so one skill tree is devoted to pistol use. The pistol option is actually viable from what I've seen. I've got one trained as pistols for the timer missions, and one traditional, and am bringing up a mixed training.
Specialist: Feels the freshest of the set. The new hacking risk reward system will have you wanting one of these hackers. Team critical boost, team concealment, team dodge, etc can all be had if you hack the enemy. Failing tends to call in reinforcements. They also work as your medic or support, really well balanced.
Scout: I am not a fan, thematically, of swords in my games with aliens. I just don't see the situation where I wouldn't just shove the shotgun in the alien's face instead of pulling out a sword. That said, I have one decked out fully in the sword skill tree, and she does kick major ass...and causes lots of bugs with her free melee attack on anything that gets that close. The other side of the tree allows more concealment than normal, which is a double edged sword I haven't figured out how to fully utilize.
Grenadier: Out of the gate, felt really weak compared to the last game's heavy. Some tech and skills later, and they've become among my favorites.
While all rookies are carbon copies, stat wise, (they might statistically equal be whithin the same class at the same rank as well, I haven't gotten far enough to tell yet) one of the rooms (forgetting which) you build adds the possibility your soldiers learn random skills as they level up. Skills outside normal tech trees. These can make some hilariously fun combinations. Characters that get free grenade tosses, or can dodge shots, etc.
Psionic: Have not unlocked.
Game likes to troll you as well...

So, PTSD soldiers. The cure is to get them through successful missions without taking damage. That's fine and good for a sniper, but the scout is going to have a rough time of it.
The AILOVES to go after the closest target. Probably the highest percentage target, really. Taking advantage of this with the device that makes a hologram of yourself, you can watch them wander out of cover to stand around the hologram swinging at air, and blast the crap of out them on your turn. Trying not to abuse this, but it's a little 'get out of jail' card I keep around when things look bad.
Certain enemies prefer certain actions as well. Sectoids are going to psychic attack you far more than use their gun. Snake men will try to ensnare you even though the gun is probably more deadly, bunched up soldiers are begging for the muton to toss his grenade, etc.
Patrols seem to be programmed to converge on your target in timed missions too, so you're better off taking out the first group you see, or they're going to come up and cause trouble later.
OverallGames these days launch buggy, poorly balance, and incomplete. This one isn't much different.
If you liked the last XCOM, you'll like this. It's still lacking that utter doom from the original. Those shots from the dark that make you jump out of your chair and leave you wondering where it came from. The alien double move is what it is, and concealment lets you play some of that to your advantage.
The timers are getting the most negativity online. It's a harsh timer, and it's over half the missions you'll play. This can be modded if it's too terribly harsh, and might be patched. If I was going to rate it fairly, I'd say right now it's a 7/10ish range. I fully expect some things added via patch, and a balance patch down the road to get it to 8/10, maybe 9, which is where I would rate Enemy Within, but recognize enough randomness that this one probably has a better replay value.