My pick is Killzone 2. It had jaw-dropping visuals at the time, some very unique technology, great weapons, a great villain and just heaps of character. Even the controls, which were slated by many, added a very unique feel to the game.
Killzone 3 opted to add a bit more colour and while visually it was more impressive, the changes took away from the grittyness of the first PS3 installment. In some areas I also found that the game seemed to have a few odd design choices and overall it was less polished than KZ2. The campaign lacked a cohesive structure, the story was all over the place, there were a few jarring technical issues and just so many missed opportunites. Certainly a major step down from the single player experience of Killzone 2. I was scratching my head a few hours in, wondering how GG got everything so wrong. There was some positive progression in this game over the first including improved diversity of environments and jetpacks...but I'm struggling to think of much else.
