How to improve the Killzone franchise into a universal critical success?

[Osc89]

pokoko said:

jlmurph2 said:
They need to realize its not just about shooting and looking pretty. You need to have a universe to have great stories, which is why Mass Effect and Halo are critical successes. Plenty of back story and material to work with.

It would appear that you know absolutely nothing about the Killzone universe.  No back story?  Seriously?

That kind of annoys me.

What is the back story? Shadow Fall will be the first one I get so I'm worried I won't get what is going on. Do you need to know what happens in the first 3?