Neil 'Exedore' Alphonso has been with Brink for http://www.splashdamage.com/content/killzone-2-lead-level-designer-joins-splash-damage and he is the lead level designer
http://www.splashdamage.com/node/359
Ohhhhhhhh, THAT guy. I saw him commenting a lot on the Splash Damage Brink forum and that's how I find out about more in-depth information about the game. He seems like a pretty cool guy. ^_^
Killzone 2 single-player-mode is the only thing I have played, but I know there are classes in the multiplayer mode (I would LOVE to have been a Medic, hee) like Brink and ET have.
From what I have heard, it seemed like Killzone 2 multiplayer has a bit of a teamwork thing there, so it's all good.
I love the game and all, but ugh, the "sluggish"/"weighty" feel of the guns took me some severe getting used to, especially after most other "light-feeling" guns of CoD: Modern Warfare, Metroid Prime 3, and Borderlands, lol.

I have to go really slow and my aim was already horrible in FPS games, so the slowness just made it even worse sometimes, lol.