Despite the less than stellar offshoot The Bureau: XCOM Declassified, the main XCOM series of futuristic strategy remains untarnished. Fans who want something more familiar to the turn-based combat of XCOM: Enemy Unknown should have their hands on the trigger for the upcoming expansion pack, XCOM: Enemy Within, which Firaxis hopes includes enough new soldier classes, abilities, upgrades, and weapons that you'll want to conquer the core title once more to experience Enemy Within to its fullest extent.
The natural extension of anything XCOM-related would be technological advancement, and to this Enemy Within will not disappoint. The human race has integrated alien science one step further with several new breeds of soldier units, including a gene-enhanced sniper who can jump onto pillars that serve as a fortified perch and mech units that can pulverize anything into pulp with a kinetic power punch.
Genetic modifications, discovered through alien autopsies, will become available in the Genetics Labs. Not only will Gene Mods alter a soldier's appearance with unique costumes, but they can give incredible advantages on the field, like Neural Feedback which damages aliens who attempt to use mind control on the user or Adaptive Bone Marrow which lets wounded soldiers regenerate some lost health. Another mod will give soldiers a redundant second heart for protection from perma-death, and Mimetic Skin will turn units invisible if they're in high cover for sneaky criticals.
MEC Troopers, enhanced from any soldier who isn't a rookie, will come with cybernetic implants that allow them to control the Mechanized Exoskeleton Cybersuit. Given their incredible armor, they won't be able to take cover, but they won't need it with their 20-unit health ar and heavy weaponry, such as the Flamethrower and Kinetic Strike Module, both of which dish out collateral damage. MEC Troopers can upgraded even further with an area-healing Restorative Mist and an area-of-effect electric attack called Electropulse that completely demolishes any alien Mechtoids and flying Seekers. Collecting the new resource called Meld strewn throughout the environment will be necessary if you wish to construct additional Mech units and upgrades at base.
Apart from a bevy of tweaks to the interface and combat which would be too long to list here, several new items will increase the survival rate of your team. Four new grenades—Needle, Stealth, Gas, and Flashbang—provide additional ways to inflict negative statuses and inflict damage on aliens without completely destroying their bodies for autopsies. The new Mimic Beacon attracts aliens with a decoy, and the new Respirator Vest protects units from the Seeker's paralyzing strangle attack. If that wasn't enough, Enemy Within also comes with 47 new maps and 8 new maps for multiplayer.
However, a note of caution: While Enemy Within is a technically an expansion pack, it mutates the core gameplay enough that you will need to replay Enemy Unknown. On PC and Mac, the expansion will be available for download for $29.99, and for Xbox 360 and PS3 consoles it will be a disc-based standalone title entitled XCOM: Enemy Within - Commander Edition which comes with Enemy Unknown as well as the Elite Soldier and Slingshot add-ons for $39.99. Whichever way you choose to purchase Enemy Within, it's slated for November 12, 2013.