Prepare for war
As stated in my review, XCOM: Enemy Within adds a lot of awesome new tools to your soldiers' arsenal. From passive genetic modifications to the walking tank-like MEC Troopers, the new inclusions are a ton of fun to tweak and mess around with. But with more firepower comes greater challenge: new aliens and a rogue faction of fanatic humans are more than eager to put an end to mankind, and you'll need all the help you can get if you're to save the world. So suit up with these tips, and get to it.
1. Go in with a game plan
The last thing you're probably looking for in a tips article is for someone to tell you to do some pre-game planning (HRNNNNNGG), but for real: do some pre-game planning. You're not going to be able to save every country unless you pull off some David Blaine street magic. Look at the satellite bonuses of each region and decide what's most important to you, and know ahead of time which countries you're willing to sacrifice. I recommend choosing Africa as your starting country, as the 30 percent increase to your monthly income will prove invaluable, especially early on. Europe and Asia provide some of the best passive bonuses for maximum satellite coverage, so you should probably protect those as best you can, too.
2. While you're at it, plan your squad setup
ANOTHER PRE-PLANNING SUGGESTION? Yes, indeed. If you're playing on the harder difficulties, you can't afford to research and build equipment at random. Once you know which countries you'll willingly abandon, figure out what type of squad setup you'll want to use and how you'll want to outfit your soldiers, so you know what to research and when. At most, you can eventually have up to six soldiers in a squad. My recommendation: go with one Assault, two Snipers, two Support, and one Heavy. MEC Troopers are super awesome, but their accuracy is pretty awful even when maxed out, and you'll have to sacrifice a ton of resources to make them a viable addition to your team.
3. Play cautiously
The golden rule of XCOM: use your first action to move into cover, and your second to enable Overwatch. Dashing is rarely a good idea and should only be used when you're absolutely certain it won't lead to an ambush. Stick to the edges of a map until you absolutely have to start moving inward. This way you can clear all the aliens from the perimeter without accidentally uncovering any that might be hanging out in the middle. Finally, be mindful of how much ammo your soldiers have left in their weapons. Nothing sucks quite as bad as moving into a perfect flanking position, only to have to reload.
4. Go for Carapace Armor before new weapons
Laser and plasma guns aren't going to do much good if they're chilling in the hands of a dead squad member. Nabbing Carapace Armor early on will dramatically increase the survivability of your troops. From there, prioritize laser rifles and sniper rifles. I found that skipping over Heavy Lasers was totally viable--by the time I could spare the resources for new Heavy weapons, I went straight to plasma.
5. Leveling the Assault class
Start by thinking what kind of Assault unit will most benefit your gameplay style. You can pick up all the extra critical chance abilities--such as Aggression and Close and Personal--if you want a high damage dealer, but doing so is a super risky move (and a pretty dumb one on higher difficulties). I'd recommend taking Tactical Sense and Lightning Reflexes for survivability, and Rapid Fire for harry life-or-death confrontations with Berserkers or Chrysalids. Close Combat Specialist is a must-have, as its defensive benefits far outweigh the crit damage otherwise gained by Bring 'Em On, while Resilience will prevent your Assault soldier from falling victim to a crushing critical strike.
Recommended loadout: Plasma Rifle (until you unlock the Alloy Canon), Alien Grenade
6. Leveling your Snipers
When you're playing it safe--as you should be in Challenge Mode or higher--Snipers will be doing your heavy lifting. You'll want to give them as many aim and accuracy bonuses as possible (ahem, Damn Good Ground), and though Snap Shot might be a tempting ability, Squadsight is the better option for passive play. You might consider equipping one of your Snipers with Disabling Shot to disarm enemies, while the other takes Battle Scanner so you can get a bit of extra vision. Execution and Opportunist are both incredibly valuable abilities, though at least one of your snipers should take the former. Finally, Double Tap is your BFF. At the start of each mission, get your Snipers to as high ground as possible, which should give them the best chance to hit your targets. They'll mostly hang back as your Assault and Support troops move forward.
Recommended loadout: Plasma Sniper Rifle (ASAP!), S.C.O.P.E. (don't forget to upgrade S.C.O.P.E.s in the Foundry)
7. Leveling your Support soldiers
These units not only provide a ton of utility, but are also your secondary alien killers. Sprinter is practically mandatory, as it'll help you get to low-HP units in time to save them. If you're running with two Supports, I'd suggest making one of them your dedicated healer, picking up the Field Medic, Revive, and Savior abilities. The other should keep your units protected--grab Smoke and Mirrors, Rifle Suppression, Dense Smoke, and Sentinel.
Recommended loadout: Plasma Rrifles, Medkits (don't forget to upgrade Medkits via the Foundry)
8. Leveling your Heavies
Heavies have horrible accuracy, but their value is in their rocket launchers and damage/aim buffs. I'd recommend skipping Bullet Swarm in favor of Holo-Targeting, as the aim bonus will likely secure shots that might've otherwise missed. Shredder Rocket is also a great damage boon for your team, especially when you've got superpowered Snipers picking off enemies from a distance. Most of their other abilities are pretty equal in terms of squad advantages, so these can be selected based on personal preference, though I would suggest going with Danger Zone over Grenadier--I tend to put more stock in building up rocket damage and area of effect.
Recommended loadout: Heavy Plasma, Blaster Launcher, Alien Grenade
9. Using MEC Troopers
If you're playing on higher difficulties, these bad boys are harder to justify because of their high resource cost. They don't become super effective until they have upgraded gear--and even then, their accuracy is worse than that of Heavies. If you decide to go through with building one, however, there are a few things to consider. First, go with Flamethrower over Kinetic Strike Module, as it's capable if hitting multiple enemies at once with decent damage, while the latter is a single target ability that requires you to be standing right next to an enemy. I also found the Grenade Launcher--which has insane range--to be more valuable an asset than Restorative Mist, and the Proximity Mine is equally useful.
Recommended loadout: Particle Cannon
10. Don't overdo it with the gene mods
The new gene mods are extremely useful--so long as you're equipping them on specific soldiers where they make sense. I really only found them to be super beneficial to my snipers. For those, I'd recommend taking Mimetic Skin (unlocked via Seeker Autopsy) for camouflaging your snipers when they have to move to higher ground. Depth Perception will increase their accuracy when they have a height advantage, while Muscle Fiber Density (unlocked by completing a Thin Man autopsy) will allow them to jump onto rooftops without needing a ladder. All of these will drastically increase the mobility and effectiveness of your long-ranged attackers. Keep in mind, any soldier that undergoes genetic modification is stuck in the medbay for three full days, so be careful about your timing.
11. Strapped for cash? Visit the Grey Market
It's easy to forget that the Grey Market exists, but it's a great way to get some extra cash when you're running low on resources. Some items, like damaged alien wreckage from crashed UFOs, can't be used for anything, so you might as well get rid of 'em. Other things--especially the mass quantities of alien bodies you'll have stockpiled in your XCOM warehouse--are less important over time, so don't be afraid to sell off some of your inventory, especially when Japan's about to bail on the council because you can't afford to put a satellite in its skies.
Good luck, Commander
Will you be picking up XCOM: Enemy Within? Have you already started playing around with Gene Mods and MEC Troopers? If so, what tips do you have to would-be defenders of planet Earth? Let us know in the comments below.
And if you're looking for more, check out how to beat XCOM: Enemy Unknown on Impossible Ironman mode and 8 awesome-looking games you'll overlook this holiday season.