Here is another game that you can unlock on Steam.
The Flagship Turn-Based Strategy Game Returns Become Ruler of the World by establishing and leading a civilization from the dawn of man into the space age: Wage war, conduct diplomacy, discover new technologies, go head-to-head with some of history’s greatest leaders and build the most powerful empire the world has ever known.
Genre: Strategy
Release Date: 23 Sep 2010
For more details about the game, click here.
In order to get the code you have to complete two easy steps:
Step 1: Share this page on your favorite social network. Feel free to use the buttons at the bottom of the page.
Step 2: Click here and complete a quick survey to prove you're not a bot.
After you get the code, open Steam client and click on "Activate a Product on Steam" on Games tab.
Enjoy!