2012's Reboot of the classic XCOM series was met with rave reviews, winning a whole bunch of awards including Best PC and Best Strategy Game awards at E3 in 2012.
However, many people criticized the reboot for not offering certain elements of the classic X-COM gameplay (such as the base defense missions and multiple skyrangers) and that being said, Firaxis have stayed true to recent form, and emulating their strategy for the 2010 strategy game of the year (Civ 5) have released a full, proper expansion pack.
Now, this new expansion pack isn't the typical map pack type thing that has been plaguing most games recently, but is more reminiscent of expansions for games like Age of Empires, where new features were added as well as new maps, weapons, upgrades, and maybe a campaign or two thrown in for good measure. Unfortunately, Enemy Within doesn't really add a new campaign, but what it does add is quite extraordinary. In an effort to shake up the combat mechanics, Firaxis have added in two major soldier-specific features- MEC Troopers (giant augmented cyber soldiers) and Gene Modding. Both of these require the construction of the Cybernetics and Genetics labs specifically, and then soldiers are merely sent off to be enhanced, similar to the process through which soldiers gain PSI abilities in the base game.
A fully Upgraded MEC-3 soldier. Note the 3 weapon upgrades on the right.
The MEC Trooper appears to be the shock-trooper type soldier that is perfect for the incursions into the areas where you don't know what there is. Initially equipped with a minigun (which has a satisfyingly destructive sound effect), the MEC trooper gradually gains more destructive weapons throughout the game, each more powerful and dangerous than the last. It follows a similar progression as the regular soldiers' weapons (Bullets > Laser > Plasma). The MEC trooper receives one of four abilities initially, depending on what class they originally were, and have their own unique skill trees. Additionally, the MEC suits themselves can be upgraded with things like flamethrowers and grenade launchers, providing formidable firepower for your team.
Of course, in opposition to this, the Aliens employ the uses of the "Mechtoid", basically the same as a MEC trooper, but it's a Sectoid driving it. These prove deadly on the battlefield, especially when a sectoid performs it's mind-meld thing and effectively cloaks it in a damage-reducing shield, making the Mechtoid more of a threat. A new enemy known as the "Seeker" also makes an appearance, and it's ability to cloak and sneak around your forces before strangling them can prove disastrous at an inopportune time.
The Gene mods are a different story. Added to regular soldiers, while they provide benefits such as aim bonuses for higher ground or easier traversal of heights, if you've selected the "mind hates matter" option in Second Wave, (as i did), implementing them means that those soldiers cannot use PSI-abilities, meaning that you have to make the choice between the two. That being said though, the gene mods are still a useful addition to your squad, and additions such as the Mimetic Skin allow you to spot enemies that you can't visually see, allowing you to plan your attacks accordingly.
In order to gain these upgrades, the new resource called "Meld" has been added in canisters on almost every map, and they are collected in a fashion similar to the bomb disarming in the regular game. Also like the bombs, they have a limited time on the field before they deteriorate, requiring a more rapid style of play in some situations.
The Gene Mod screen. Only one mod can be chosen for each category, but they can be switched at will.
All of the upgrades from Within are integrated into the regular research tree, meaning that as you do things like autopsies and interrogations, you unlock these components for use. It fits seamlessly into the rest of the game, much like the other big feature added by Within...
Serving as secondary antagonists to the campaign in Enemy Within is the organisation EXALT, who appear to sympathise with the aliens, and through that, become your enemy. They have an annoying habit of stealing your hard-earned satellite cash and generally making life at XCOM a hassle, but it's on the battlefield where they prove to be more challenging. In order to remove them, you have to engage in a series of "covert operations"- basically sending a soldier in for a period of time, then extracting him. The missions involving EXALT provide a fresh breath of air to the "Kill Aliens" missions.
They emulate tactics of the XCOM forces, employing things like smoke grenades and rocket launchers to try and impede your progress. Usefully, any of the weapons that you collect in battle against them can be either used or sold on the grey market, providing an alternative source of laser weapons (or income) later on in the game.
Also added to the game are a number of immersive features, including the ability to have your soldiers speak in different langauges (French, Spanish, German, Italian, Polish, and Russian) as well as extra customization options for your squads. The inclusion of medals is an interesting addition, and the fact that you can award them to whichever soldiers you want is a useful addition. The buffs that these medals provide can prove as useful as any Gene mod or buff added.
One of the new MEC troopers ingame.
XCOM: Enemy Within adds a lot of content, and the addition of 47 new maps in total as well as the reworking of several of the old maps provides a veneer of gloss on an otherwise satisfying game. The addition of much of the new content to the multiplayer as well (including the base defence map, hooray!) also expands on a mode that is actually quite well done, if a bit overlooked, and makes it something that you're more likely to dip into at some point. It provides another reason to play through the campaign again, and the addition of more second wave options (save scumming, also hooray!) means you'll continue dipping into XCOM for a long time to come.
XCOM: Enemy Within is available at all good distribution websites (Steam, Gamersgate Greenmangaming, Gamefly, etc.) for PC, and available as a seperate, self contained game with Enemy Unknown and the preorder DLC for consoles. Priced at $50.