I was playing it yesterday and I think I'm near the end of the game. I didn't exactly have high expectations, but it's decent enough. That said, the story and progression have been weak.

Pretty much this.

Killzone 2 has the best campaign while Killzone 3 has the best story.

I just really like the series because it isn't water down run and gun gameplay with absolutely no story that the masses buy every year.

http://twitter.com/#!/Noodle_Doodlez/status/111441612961353729/photo/1/large

Thats the link to my stats I took a picture and uploaded em...as you can see I finished the campaign a lot faster than the so called "8-10" hours it took those other guys to do it, and I highly doubt they played it on hard...Like I said, the campaign was good until it ended because it just suddenly ended. There wasn't a real wrap up to the story, and about the boss fights, there are only 2 fights I consider boss fights, There isn't a giant mech boss fight that's just a giant set piece where you really don't do anything, the only real boss fights to me is the Widowmaker boss fight and the Brawler boss fight,...The story was fine. So I apologize for enjoying Resistance 2 so much that I had extremely high expectations for Resistance 3 which were shot down by the crappy beta that didn't even work it's first week and was a total lag fest untill the last week. I guess people can't have an opinion if it differs from what official review sites state. The same review sites some idiots will applaud if they give a 9.0 to a game they love without playing and then demand blood if a game they love recieives a 7.5....immaturity at it's finest folks. 

edited to take out spoilers since I can't seem to find how to do that with a highlight tool anymore - Tor

You do know that most campaigns these days are short right?
Anyway most reviews I read said to play it on hard in your first playthrough. I guess you shouldn't read some reviews!

Having finally beaten the campaign... yea I must agree that it was rather disappointing. Unless I missed something somewhere, the full story of the Chimera doesn't exist. They're just there and any further details are "I guess we'll never know" which is annoying because the other characters just aren't interesting so I'd at least like to know the back story to the damn enemy who is so monsterous.

^

I guess someone didn't play R1 or R2 to figure that part out.

Funny, I just beat the game and I thought it wasn't disappointing at all, in fact I was impressed.

Indeed I have played them, it's just that there's still mystery and there's some vagueness to what does get explained in the game usually leaving other tid bits to be found in the intel.

Funny, I missed the part where my opinion was fact and nobody could disagree with me.