Killzone 2 is not having issues with development. Things are not behind. The reason the title was pushed back to February 2009 is simply that Holiday 2008 is already stuffed with some great shooters. Yep. According to Sony PR Rep Ron Eagle:

Just wanted to add a quick reply on the “delay” of Killzone 2 to Feb 2009. To be clear, there is nothing wrong or causing a delay to the development of the title. We (SECA) had to look at the fall calendar with SOCOM, LittleBigPlanet, MotorStorm: Pacific Rift, Resistance 2, plus some PSN titles and make a decision where each game should come out. Killzone 2 was moved to Feb 2009 to make sure we didn’t have three shooters in the marketplace competing for retail dollars during the same holiday season. The game will be great and it will be out in Feb 2009 in both Europe and North America.

There you have. Straight from SCEA. The game is on schedule, but too many other great games are on tap. You’re just gonna have to wait.