At first glance, the March NPD numbers seem unpleasant for the sales of Killzone 2. After debuting in fifth place of the software charts last month and slipping to seventh this month, one could get a gloomy picture of the PlayStation 3's killer app. But it's important to remember that the game was released on February 27, giving it only two days of sales for that month. Since game sales are front-loaded near their release dates and fall off considerably afterwards, a more accurate estimate of its first month sales would come from combining the February and March numbers. This brings the game up to 619,000 copies sold so far in the U.S. If placed that way in the March charts, this puts it in fourth place, just behind Halo Wars at 639,000.

Looking through this perspective, the sales for Killzone 2 seem much more positive, but there was still reason to expect higher numbers. Before the game was released, it was widely reported that European pre-orders for the game had reached 1.1 million. Oddly, tonight Sony announced (via Kotaku) that the game has sold over one million copies worldwide. It's a great milestone for the game and most publishers are happy to reach the million mark, but considering the pre-order numbers something seems off.

We know that about 600,000 of those million sales came from the U.S., so the remaining 400,000 in Europe isn't even half the pre-orders reported for that territory. It's possible that the early reports were mistaken, and instead referring to worldwide pre-orders. But that would mean that the game sold almost no copies that weren't pre-ordered. Alternately, those who chose not to pick up their pre-order copies could have been offset by regular purchasers. Still, maintaining a near-exact number seems strange.