Need a facebook account to get the code. You enter the code on Steam. Steam is a app where you buy and manage some of your PC games.
To prep gamers for the release of Metro: Last Light next year, THQ today announced plans to give away copies of the original Metro 2033 game through Facebook.
Starting today and continuing through Dec. 16, community members of the official Metro Facebook page will receive a code for a free copy of the game for Windows PC, while supplies last.
Saw this in the recent news on Steam after getting Metro 2033. Essentially, you can pay next to nothing for these games. Saint's Row The Third was the only one I really wanted so I paid more than the average $5.74 to unlock it. Still a great deal.
It's not like Fallout, more like a standard fps single player game. Maybe some survival horrorish stuff. You have to manage oxygen and bullets = currency. You can use the good bullets for shooting or to buy nicer stuff. The cheap bullets are weak and inaccurate though.
