Firaxis' reimagining of XCOM: Enemy Unknown will arrive on Steam this October with tiered pre-order bonuses.

Firaxis' reimagining of XCOM: Enemy Unknown will arrive on Steam this October with tiered pre-order bonuses.

Buyers will help unlock pre-order rewards with their purchases. Each purchase will increase the percentage of the rewards bar – when the bar for Reward 1 reaches 100%, all pre-orders will receive the XCOM Elite Soldier Pack, which includes the tools for soldier customization.

The second reward, which will be unlocked if enough people pre-order the game, includes the Elite Soldier Pack as well as three exclusive XCOM Team Fortress 2 items: The Crafty Hair, Area 451, and The Vigilant Pin.

The third reward includes all of the above plus a free copy of Civilization V. If buyers already own the game, they can gift it to a friend.

XCOM: Enemy Unknown will be available on Steam on October 11, 2012.