"It seems that Killzone 2 mania has reached fever pitch as the game has been selling quite well just from pre-orders alone. However, after a quick survey around the retail chains, it seems that the game is selling just as well from walk-in purchases. In fact, in some retail channels the game has completely sold out.
It was announced that Europe alone had 1.1 million pre-orders for the game, which is phenomenal when you consider the fact that our brethrens across the pond really don't care for pre-orders as much as we do. It is unknown exactly how many pre-orders were placed within the States. Sony has already revealed that Killzone 2 broke just about every pre-order record they have for first party games."