Usually Sony's initial PS2 game promotion starts 6 months ahead of anticipated release. I'm surprised they are already promoting this game.
I know they cut some stuff out of the original God of War 1 which was stated to have been very cool, but due to technical limitations these ideas had to wait to be implementated on the Playstation 3. Maybe they started to plan the game way before the first PS3 dev kits became available, story, art, concepts, etc can be worked on before having a PS3 dev kit.