I will agree that the first KillZone wasn't graphically better. But the online game play is completely different. I liked the KZ online play better than Halo 2. In fact H2 copied KZ's "levels" idea.
Now KillZone: Liberation I see is a redemption for their graphics. The game is AWESOME!
Now KillZone 2 is looking 3 times as good as Halo ever will be. Seriously H1 was the first engine build but 2 and 3 used the same engine between each other. Bungie didn't want to create a new graphic engine for Halo 3 seeing how "They never finished the fight."
H2's story line had the worst cliff-hanger ever. And playing with the EMO arbiter was a dumb idea. "Oh lets give him the ****iest weapons and armor ever! We will put him with the stealth team and see how he does." Seriously idiotic. If they really wanted to win that war they wouldn't even do that to a single soldier. Its more flawed than kingdom paradise's story.
Halo is way over rated but KZ1 got the rating it deserved for the graphics bit. Everything else with KillZone was awesome. Sorry but KZ2 has so much going on in the background that it would take 3 halo 2 engines to run the game.
Heroes get remembered,
but Legends never die.