Yes, there's a version for Enemy Unknown too, but it isn't nearly as good. XCOM: Long War is a free mod for XCOM: Enemy Within that maintains the core gameplay but overhauls the entire system to add a depth and breadth of soldier customization, strategic options, and much more. And now there's a mod that's so good it makes the expansion pack feel like a tired retread. Its first expansion pack, Enemy Within, added so much amazing content that it made playing the game an entirely new experience.
XCOM: Enemy Unknown is a great tactical game from Firaxis games.
