XCOM: Enemy Within

XCOM®: Enemy Within is a standalone expansion to the 2012 Game of the Year award-winning strategy game XCOM: Enemy Unknown. Enemy Within features the core experience of Enemy Unknown plus even more content including all-new soldiers and abilities, enemy threats, maps and missions and multiplayer content providing a fresh new gameplay experience. Also included is the Elite Soldier Pack, plus the Slingshot and Second Wave add-on content.

New Soldier Abilities: Research a new alien technology to advance the capabilities of your operatives
New Weapons and Equipment: Give your operatives an extra tactical edge with new projects from your engineering team and the Foundry.
New Enemy Threats: Adopt new tactics to counter the threats from two new alien classes including the Mechtoid.
New Strategic Resource: A valuable new alien resource, known as MELD, has been released onto the landscape providing access to new research and upgrades.
New Tactical Challenges and Maps: New tactical challenges are introduced across an additional 47 maps.
New Multiplayer maps, units, and abilities: Create your custom squad from a wider array of options and dominate your opponent in intense, one-on-one, turn-based matches.