So, just finshed the first round of XCom: EU on Normal. Not exactly the best in storylines but I've heard worse.
So, what to expect if you pick this up.
1) Don't rush the main mission unless you're confident about the last few fights. Each time you push it forward you also push up the difficulty of the fights from then on. There are certain points you can stall it (usually you need to build a base structure or capture something specific). You want to do this (within reason) unless you're on Normal or Easy.
2) There's no significant 'escalation' of events. You never end up in that 'oh my god it's going too fast!!!' feeling. The race is completely based on the panic timers and forced 'choices' by the abduction missions.
3) On Normal, I was able to keep all the countries under extreme panic, but it was a near thing a few times. On Classic, you're simply going to lose a few, period.
4) Research is VERY limited. Concentrate on Engineers, not researchers. That reduction in price is worth 10 fold of what some faster research will get you. I wasn't even trying to kill the tech tree and I blew past it. It's all about the Benjamins (Engineers reduce price and material usage).
5) Missions basically come in one of five forms.
Kill EVERYTHING: normal mission. UFO crashes, Abduction Missions, etc. You vs. them, KEEEL.
Bomb Site: Timed mission to keep you moving towards a flag, which you then defend from a final spawn. Not usually overly difficult as long as you don't over-extend.
Gauntlet: Really, they're base missions, but it's a gauntlet run. Not all that particularly different from Kill everything but flanking maneuvers are very limited and usually you're chokepointed multiple times.
Terror Missions: These are easy to fail early on, after that it's more a race to see who gets to the civvies first without throwing your troops into the middle of 3+ Cryssallids who will do significant damage to you even in Titan armor if they get first punch.
VIP: These are very rare. Run across the map, kill everything, then double check, then 'tap' the VIP who's safe until then, and guard him back to the extraction zone.
6)The inventory system works well enough. You lack rediculous customization of your backpacks and everyone doesn't get a medkit anymore but it does keep things moving, instead of spending an hour or two gearing up for a single mission.
7) Mission times: About 20-30 minutes a piece. My average match was 11.6 turns apparently, and the middle of the mission usually turns into a 100 meter dash as you cross the center of the map to get the guys in the OTHER corner. I'd say Normal game length was about 40-50 missions long without being a completionist. The first few missions take a while simply because you need to get used to the controls, and later on your guys have more abilities available. My first Colonel was a sniper who could double-tap anything across the map that the squad could see... so things sped up a LOT at that point, if I could get him a decent vantage point.
World Coverage: The satellites are there as much, or more so, as one-shot panic reducers as they are for ship detection. You don't get many ships detected, maybe 1/month, even when you have the 'ultra-detection array' from the storyline... slightly hidden for spoilerage. For perfect build you end up needing 4 Sat Nexus with the special Sat Nexus in the center in a cross to get all 16 sats up.
9) Game Pacing: The game is better paced in the beginning than it is at the end. I was rushing the storyline and was willing to take reasonable losses on any mission. At the beginning, it's a good struggle, nice tactical/strategical challenges. Near the end it's a game of one-shots, as 90% of the enemies critical like mad, but so do you with your 'big guns'. Pistols and off-weapons get nearly useless as you get closer to the end, though it's not usually too hard to get even the biggest of critters into taser range for a live interrogation. The closer you get to the end, the more cagey you need to get to make sure you're the first one to fire. Alpha strike rules.
Troops:
Favorite unit composition: 2xAssault with Ghost armor, 2x Sniper with skeletal/ghost (gets them to rooves) or titan, one heavy in titan, one support in psi-armor. Go medic with support, go gun-happy with the heavy.
Psi-powers were really powerful in the first game, in this one they're so-so. I made use of them but the real ability you want, the one that disconnects a friendly from an enemy's mind control, isn't there. The Mind-hack is the first power you get and the one you'd use the most often. It's best on snipers usually so they have an alternate to the pistol, and assault with defensive skills lets you defensively back them up with each other while popping things around corners. Support however is the medic, and he's usually the one in odd positions where his defensive psi-positions can help protect the guy he just healed, as usually that's the guy that's deep in the crap.
In most missions your 6 troops will end up facing off against 8-20 aliens. However, at least in Normal and what I saw of classic, NOONE brought a frickin' radio. Until you 'awaken' a particular spawn of aliens, they just keep doing their thing, whatever it was. You end up purposely going very slowly, waking only one group of aliens at a time. They travel in groups of 2 to 4. Those aliens will attempt to flank/get cover/etc. Also, they get a free move to run for cover anytime you uncover them, unless cloaked in a ghost suit (max 1 turn before discovered, even if you recloak) or detected via the scanner from the snipers, who are usually way the hell in the back. All of that 'open doors quietly' crap is useless. Go loud. The only time I used it was because the cover was better at the doorway.
The robotic troops (S.H.I.V.s in this version) suck, as usual. They probably beat out rookie/squaddies but that's about it. The hover DOES make a decent scout for a heavy sniper team with squad sight though, it just doesn't last long.