How did Guerrilla pull of its distinctive "Killzone look?" Their Develop presentation was all about "deferred rendering," a process which adds Hollywood-quality visual effects to the images rendered by the PS3. Extensive post-process effects allowed the team to create "highly dynamic lighting in environments" with "complex geometry" and "MSAA" -- whatever that is.
Those with technical know-how will appreciate the Develop presentation the team delivered, which goes into some intricate detail about how much SPU power is being used by the game. Even with already-impressive results, the team has a long way to go. In fact, there are still "a lot of features planned," such as: ambient occlusion, contact shadows, shadows on transparent geometry, more efficient anti-aliasing, and dynamic radiosity.
Read - Presentation (in PDF form)