Because I liked Killzone better than Killzone 2 and even I knew back in the days that Killzone wasn't an AAA game (though it was close IMO)

it's a matter of opinion on the reviewer's part. as i said before, both titles are fantastic games. reviewers may factor in other things, like story, online, singleplayer elements, etc... i'll bet that you can find plenty of ps3 titles that recieved vastly superior reviews to their 360 counterparts.

Killzone 2 is a great game, but it isn't in the Halo series league. Halo set standards while KZ2 learned from their mistakes and took a couple  of things from their playbook hoping to be somewhat on par. Graphically, it is beyond Halo, but as far as gameplay, multiplayer,online offerings and customization it is nothing compared.

Well the reveiwers just liked Halo 3 better (for good reason)Most peple won't understand how awesome Halo is untill they play it a good amount...

Well what kind of answers are you expecting then? There's no vast conspiracy against Killzone 2. It just isn't as well liked by the PS3 fanbase as Halo 3 is to the 360's fanbase. Simple as that. Reviewers didn't like it as much, and neither did consumers. There is nothing definitive that can be said about why, just speculation. Frankly, if Killzone 2 were on the 360, it may have had a chance to see triple the sales under a better marketing onslaught from MS.

Also Killzone 2 is not a must have for all Playstation 3 owners. I should know since I own a PS3, Killzone 2 and I regret the game purchase entirely.

I like your answer, though for some reason both games have a bad habit of chocking down what could be a vast series of liner levels where you should be able to run back and forth in them if you want to... always erked me they kept making halo levels smaller and smaller. well that and the decreasing interest in the story.... SP halo:CE for the win  ...   and a mighty and continuing leap in online multiplayer for every on and every platform    

I think that people were expecting way too much from killzone 2, and in many ways it delivered. Halo already had it's winning formula and simply had to improve on it. IMO killzone 2 is way better than Halo 3 in both gameplay, story and production values. If both games were released in the same time frame, killzone 2 would be rated higher.

The reason is this: Because Halo 3 is better than Killzone 2, simples!

its easy halo 3 has way more features. 4 player co-op. great controls. huge online features its just a great game. has clans and match making where you can bring all your friends. etc

Killzone 2 they had to update the controls. no co-op offline or online. plus many other things

(and this is coming from a sony fan who owns both btw)

both great games but halo has it in almost everything but the graphics.

I found much more fun playing Halo. So, I'll give it higher score.