UFO: Aftershock iis a real-time strategy game that is similar to Aftermath in that it follows in a similar vein to the X-com games of yore. That said, Aftershock bears even less resemblance to the X-com series than Aftermath did, so let's stop comparing them now. Aftershock, like Aftermath, has many quirks and tricks you must learn in order to succeed. While it's significantly harder to die outright in Aftershock than it was in Aftermath, that's no reason for you to get cocky; mistakes can still screw you over, so you must do your best to avoid making any. With that in mind, here's some tips for people playing the game for the first time. Note that this is just my advice, and not a complete guide on how the game can or should be played.
1. Forget everything you learned while playing Aftermath, if you've played it. Most of it doesn't apply anymore.
2. At the beginning of the game, you'll be kind of short on guns and ammunition, particularly if you're using the non-replenishable reticulan laser weapons often. For that reason, your first priority when the game starts should be to research how to manufacture ammunition and basic firearms. Unlike in Aftermath, you do not automatically replenish ammo you spent from your supply pool.
3. Changes in UFO: Aftershock are mostly time-based, in that you'll often have a warning countdown before a big plot-event happens. All the other triggers are based on your Laputa Lab research; the game will not advance until you have discovered the next part of the plot. If you wish, you can make this work in your favor by putting off plot-important research until you're sure you've got enough weapons to take on whatever the next challenge is.
4. For every character in your group, you've got a choice of three factions: Human, Cyborg, and Psionic. Humans are the only group that can wear customizable armors, making them generally better for defense. Cyborgs can get implants to boost their stats far above average. Psions can use psionic equipment to boost the power of your squad or cripple your enemies, and also detect the presence of other psions. If you want to make life simple for yourself, playing with only humans isn't a bad idea, but a diverse party may be more versatile.
5. Every character in your group can learn up to three professions, each of which enables the character to learn how to use specialized skills and equipment. How useful these professions can be varies, but it's a good idea to pick professions that complement each other, and plan out in advance what professions a given character should have. My assessments:
Commando: Commandos can use katanas, airguns, and other "stealthy" weapons. That said, stealth is overrated, so I recommend not bothering, especially since the commando weapons don't do as much damage as the weapons other classes get.
Cyborg: Only available to Cyborgs. This enables cyborgs to use cyborg implants. Since the implants are the only reason why you'd ever want a cyborg on the team, this is important for all cyborg characters.
Gunman: Gunmen can use heavy armor and big machine guns. In the middle section of the game, this is a fantastic class, but may start to fall out of style by the time you've figured out Warp weapons. Still, it's a class I'd recommend for any human character you expect to be getting close to the enemy a lot.
Leader: Leaders provide stat bonuses to squads they are a part of. Very useful, but mind that you don't put more than 1-2 in a squad; I don't think the powers of multiple leaders stack.
Medic: Useful, but not as useful as you might think it would be. Unlike in Aftermath, you can't just heal battle damage during a mission to reduce a character's hospital time, so while it's a good idea for everyone to carry a medkit, there's no reason for anyone to actually have medic training.
Psionic: Only available to Psionic characters. This enables psions to use psionic equipment, so Psionic is as important to psions as Cyborg is to cyborgs.
Ranger: Rangers get bonuses to close combat and the ability to dual-wield close-range one-handed weapons. Fairly useful, especially if you give a dual-wielder two Colt M4's.
Scout: Scouts can analyze an enemy's stats and use various bits of detection equipment. The stat analysis is nice, but the rest of it is largely useless.
Sniper: Use sniper rifles. Damn useful, especially once you get the ability to shoot people in the head for an automatic critical hit. You can one-shot most living enemies that way.
Stalker: A different kind of Commando, with more stealth and fewer cool weapons. Not any more useful.
Technician: Techies can build drones, plant mines, and use scanners, three things that you will never be required to do and which aren't as effective as simply finding the enemy and shooting him.
Trooper: Troopers can use rocket/grenade launchers, and also get a bonus for using rifles. It's a nice class in theory, but in practice you'll probably find that you don't get a lot of mileage out of explosive weapons in this game. Still better than commando, though.
6. There are many weapons in this game, and they have many different uses, except for those which have no use whatsoever. The most powerful/useful weapons by far are the Warp Rifles, but those are the last guns you'll ever develop. Until then, keep in mind the following advice:
A. Generally, alien weapons do more damage than the equivalent weapons you can make yourself. However, you can't manufacture alien ammo, so be conservative with them.
B. Shotguns do great damage, but only at close range, and don't work well against armored targets. Plasma shotguns, on the other hand, work well on everything, but their range is even shorter and they really guzzle ammo.
C. AP rounds are better than normal rounds. Always.
D. Explosives are hard to aim properly in this game, especially grenades. For this reason, don't expect more than one in three shots to hit near any given target. However, you can do a little to offset the overall inaccuracy of these weapons by using phosphorus/acid types to set an area on fire.
E. non-Warp rifles do not do as much damage as a shotguns and lack the range of sniper rifles. Some, particularly plasma rifles, also have serious accuracy problems. Submachine guns have similar issues on top of an even shorter range. Heavy machine guns, however, work well at close range and medium range, and although they're not the game-breakers they were in Aftermath, they're still relatively effective.
F. Some guns do nonlethal damage, which is great for when you want to capture an enemy and pointless at any other time.
G. All weapons can be improved by adding bits to them to increase their accuracy/damage. I highly recommend under-barrel laser sights and accelerators whenever you can use them.
H. Early in the game, you can save on ammo by using a knife to kill unconscious or stunned enemies. There's not much point do doing that once you can make your own bullets, though.
7. It's a good idea to make sure your squad has weapons suitable for the enemies you expect to encounter. Mutants, cultists, and aliens all have their own preferred weapons and armor types, so outfit your team accordingly.
8. Make sure any given team member has at least two weapons; one short range and one long range, or one laser and one projectile, or one explosive and one non-explosive, or one slow and one fast. The more weapons you carry, the more prepared you'll be.
9. Regarding tracks: tracks cost resources to maintain, and despite what the game and manual tell you, you don't need a lot of them to bring in resources. Tracks don't bring in resources; bases do. Therefore, all you need to do is build tracks between bases. Don't worry overmuch about constructing multiple redundant tracks in case one fails; none of them will fail, ever, if you're diligent about defending your provinces.
10. You can get militia/secret police in this game, but there's not much point to those because all they do is absolve you of the need to do some missions, and generally fail at that. Instead, focus your base-building on research and construction; also keep in mind that regions that have a base with a high knowledge-level output more resources.
11. No matter how hard you try, you cannot completely eradicate the cult. If you destroy their last base territory, they'll just reappear and automatically seize another base elsewhere. Just whittle them down to a single base and then don't bother with them any further.
12. You can only have up to 7 people active in the party at once, and with the Squad system it's easy to swap out people and equipment. Therefore, you shouldn't stress about making piles of equipment for each individual character. Do try to make sure the everyone has plenty of ammo, though.
13. Don't conquer all the unexplored provinces in the entire world until you're prepping to attack the alien space-ship and/or have finished researching plasma weapons. Why? Because the only way to get Warp weapons in this game is to first discover a wild Reticulan who is using one, and if you take over the whole world too early, there won't be any wild Reticulans for you to fight unless you start losing provinces on purpose. It's counter-intuitive, I know, but the payoff is worth it.
14. Remember, you can save in them middle of a mission, and if things are looking bad then you can always reload.