dolemit3 on 22 July 2008
Here's a post E3 article (dated July 20th/2008) that states that Gears of War sold over 5 million units:
Gears of War 2 (Xbox 360)
The first game sold over five million copies on the 360, and this one should sell even more. While the game play mechanics look fairly close as the first one, everything in the sequel screams, "Bigger! Badder! Better!" Think "Aliens" from "Alien" levels of upgraded awesomeness.
Follow the link and scroll down to the Gears of War 2 section:
Currently playing on PS3: God of War III
Currently playing on Xbox360: Final Fantasy XIII
Currently playing on NDS: Chrono Trigger
