XCOM: Enemy Unknown is due for release on October 9th for the PC and other platforms. However, the folks who purchase the PC turn-based strategy game ahead of time via Steam can hopefully unlock some cool rewards, if enough people jump in to pre-order the game.
The Steam page for XCOM: Enemy Unknown shows that there are three reward tiers for people who buy the game, if they reach certain pre-order goals. The first goal will unlock the The Elite Soldier Pack, which will add the Classic XCOM Soldier character in the game, along with Soldier Deco aesthetic armor items and the ability to change the colors for armor sets.
The second reward tier will add three new XCOM-related in-game items for Valve's multiplayer shooter Team Fortress 2. The items are shown above and include the "crafty hair", an Area 451 mask and the Vigilant pin.
Finally, if enough people pre-order the PC version, the last reward tier will unlock a free Steam code for Civilization V, the last major game from developer Firaxis. People who already own the game can give their extra Steam code to a friend. Normally the game costs $29.99 on Steam.
As of this writing, the pre-orders have generated 57 percent of the amount needed to reach the first reward tier with over a month to go.
Source: Steam XCOM: Enemy Unknown page | Image via Valve