Heavy memory demands from Killzone 2's high-detail warzones mean that Guerilla's opus simply couldn't work on any console using standard DVD discs.
"Xbox 360 doesn't have Blu-ray," Hermen Hulst, managing director at Guerilla explains, "PlayStation 3 does. [A single level] is 2GB. We really need Blu-ray to make the game. I don't know how you could fit it on Xbox 360 without taking some shortcuts".