I was very excited to pick this up and unfortunately my excitement soon turned into general disappointment.
The single greatest part about Killzone 3 is it is levels. Not that they are special in a free roam since but more so the amount of realism portrayed and graphic quality is a step above any other FPS or shooter style of game.
The "cover" aspect of the game should have never been implemented. It should have been called "Hit this button if you want to receive a headshot from behind a wall".
The lighting made it difficult for certain enemies to be seen. Whether this was intended or not I do not know, however the AI sure as heck knew where I was regardless of any outside influence. There were levels of difference I noted in killing the same types of NPCs. You could shoot one guy in the head twice and take him out, and then kill his equally designed partner in 20 heat shots. Didn't make much sense. There was a general lack of direction in a lot of different places throughout the game that was disappointing.
Most of the levels, although beautiful, almost reminded me of a tunnel shooter, very confined.
The single player campaign was definitely a letdown and there was nothing special or unique about it. Gears of War, Call of Duty and Bad Company all have it beat in terms of play quality.
On the multi-player side of things Killzone 3 really does shine. It's a great change of pace comparatively speaking in regards to how matches are carried out. Paired with decent levels and excellent graphics, it's quite enjoyable. The single best aspect of the game was indeed the multiplayer. Other then that... it's just an average game that's a letdown in turns of hype. Anyone giving it a 9 or 10 is just drinking hypejuice or is a mega fanboy who is wearing his (or her respectfully) fanboi overhype glasses.
I like FPS games and I end up trying most of them. I like the sense of weight that Killzone has (feels more like Gears of War than Call of Duty). Overall I think it is a good game....but misses in a few areas for being a must buy. For me it replaced COD....but for most people I think it falls short.
1) gun play is satisfying (shooting and moving feels like battle)
2) graphics are good (not quite as good as I hoped though)
1) campaign is short (and kinda lame story, but who plays FPS for story....and frankly most FPS campaigns are pretty short)
2) there are only 5 maps in the multiplayer (I'm sure more will be added....but not enough at launch)