A free weekend is now underway on Steam for XCOM: Enemy Unknown, accompanied by a 75% off sale on the sci-fi strategy game. On a related note, there is also a new announcement of a pre-purchase incentive for XCOM 2, the game's upcoming sequel. Those who commit in advance will receive a free copy of the Resistance Warrior Pack. Word is: "Customize your squad of resistance fighters with bonus outfits, headgear, and custom facial war paint. Instantly unlock a survivor of the old war as a recruit in your barracks."