Killzone is a futuristic first person shooter, where you are defending the civilized world from an attack of angry mutant rebels.
This is very mmuch a combinations of WW2 trench warfare combined with spaceships and advanced weaponry. You start out in a brown-grey combat zone, hiding behind bunkers and shooting away at the incoming attackers. The game does a good job of really immersing you in this world. The sounds of war are all around you, the moke and blasts obscure your vision. You duck down as you reload, and your hands shake as you shoot. Bullets actually hurt you, compared to games where you seem to have a Terminator-like ability to absorb barrages without harm.
Your environment has a good eye to detail - and is about as detailed as the PS2 can handle. Bushes have leaves, barbed wire has spikes. The people you meet really do seem like realistic individuals. The smoke clouds and fog are quite impressive. Yes, it's not photo-realistic, but you quickly get drawn into the world that surrounds you.
The AI is reasonably good. Sure, the characters make some stupid decisions sometimes, but people do that in real life too. If the computer actually played every enemy as a top-notch super intelligent, super fast being, humans would rarely have a chance to win :) If your side was full of super-strategic people, why would they need you? Even with their faults, your squadmates each have their own strengths and weaknesses and it's up to you to deploy them properly.
There are a ton of details in the game. When you climb a ladder, you can actually look around from where you are and it feels like you are at that spot. When you reload, you actually look down at what you are doing.
For those looking for a quick-fix arcade blaster, this game might not be a great fit. It is grey and dingy, not bright and colorful. Aiming takes skill, not button mashing. You have to be strategic and look for appropriate cover to take out your enemy, you typically can't just run-and-blast and expect to survive. Also, the language is pretty foul. These are hard core soldiers who aren't very PC.
But if you're willing to put in the time and build up your skills, and if you're looking for a serious combat simulation that rewards patience and planning, you really should give Killzone a try. I know many people who are completely addicted!
Buy Killzone from Amazon.com