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You will go from certain box or corridor like areas to another, in sequential order as you defeat waves of enemies. You will go along a relatively linear and controlled path (there are however numerous levels that allow you some degree of freedom to how you approach a particular area or gun fight), it does have a linear story with fairly straightforward progression. However, none of these things necessarily take away from the game or the merit of how well it does these things.
What Killzone 2 does is take all these elements previously found within the genre, and execute them with such cinematic splendour, realistic tactility, aesthetic beauty, technical wizardry, rewarding satisfaction and polish, that it ends up defining its own little niche. This is the true Hollywood multimillion dollar blockbuster come to gaming, but with an added raw and cut throat pang.
Whilst you may have done similar things in other shooters that you will be doing in Killzone 2, the chances are you will have never done them quite like this.
Take shooting a shotgun for example, a common weapon in most shooters. I've not found one of them as satisfying as the one in KZ2. The moment you pull that trigger you become the harbinger of death. Heads will fly; blood will gush out in an over exaggerated spherical explosion, you will hear the crunch, crack and squelch of battered body and you will see the enemy fly back in completely believably fashion. And you will love it. And you will want more, and more. And that is what separates KZ2 from other shooters. It is true gun porn.
This is the most realistic, cinematic and tactile shooter to grace a system. And while it may have its flaws, it's polished to such perfection that you'd be hard pressed not to forgive most of them. Aside from the lack of co-op (a sorely missed feature, but one made up for with everything else on offer), there's an engaging highly repayable epic SP campaign, an extremely sophisticated and comprehensive online multiplayer component, numerous unlockables and more. This game is fantastic value for money, and stands a chance at being the PS3's "it" online shooter for months if not years to come. It's also the best show piece graphically for the console yet, so as long as you're not expecting anything overly innovative and not expecting Oscar winning performances, go grab the game now. In my honest opinion it is one of the, if not the best shooter of the generation and I say that after completing the game 4 times and putting in over 100 hours in the multiplayer.