Released in 2009 by Guerrilla Games as an exclusive for the Playstation 3 Killzone 2 is the sequel to Killzone on the Playstation 2. The story continues from Killzone and Killzone: Liberation for the Playstation Portable with the war between the Interplanetary Strategic Alliance and the Helghast. You play as Sargent Tomas Sevchenko or "Sev" on the campaign of Helghan the Helghast homeworld with the goal of capturing Scolar Visari the Helghast leader this takes place after the successful campaign on Vekta.
Pros:
Presentation
The Playstation 3 flexes it's graphical muscles as the visuals in this game are outstanding so much so that I would have to say these are the best graphics in a first person shooter to date. Lighting seems to be an emphasis for Killzone 2 as the heavy use of light and shadow effects adds personality to every level while making it look good at the same time. The soundtrack for this game is phenomenal with its orchestral sound and powerful vocals it fits every level of the game nearly perfectly.
Combat
Fights are a bit slower compared to other first person shooters but the speed of the fights fits the game well and as an added bonus it makes battles against the Helghast soldiers more intense by emphasizing more tactics rather than tons of bullets.
Artificial Intelligence
The enemy artificial intelligence is one of the high points for Killzone 2. The Helghast soldiers react realistically to your attacks. If you give them an opening they will take it without remorse and even if you do not give them an opening they will make one by any means. The allied artificial intelligence is not as good as the Helghast's artificial intelligence but it is not terrible. Your allies will engage the enemy as effectively as they can but some times they have hiccups in which they are not in the right position or they do not use cover efferently or they just plainly get in your way. On a side note your comrades cannot die no matter how many bullets they take but they do become injured or incapacitated in a sense that requires you to run over to them and get them back on to their feet which can be somewhat annoying or you could continue on your mission until you reach a checkpoint either way they will be just fine without you for most of the time.
Multiplayer
Even though I haven't played the multiplayer feature of Killzone 2 very much but I can see my self being engrossed in it. The multiplayer features fairly balanced maps and is class based my only grips toward this feature is that there are no vehicles and downloadable content that you have to pay for to continue using this feature to it's fullest.
Cons:
Story
The story in Killzone 2 isn't the most original story used in the genre and you will probably forget about it after you have stopped playing the singleplayer game for a while. The characters aren't the most memorable either so you will probably forget about them as well.
Overall I would rate Killzone 2 as a 8 out of 10 Sony might have found itself a Halo killer considering the lackluster show of Halo 3 or something close to it. So rent it today and give it a try.