Killzone 2 has proved on many fronts. Graphics, game play, sound, etc you name it.
I'll start with Graphics. When Sony showed that Target render at E3.. it doesn't justify how good this game looks! It has a gritty atmosphere which is why you don't see many bright colors and i get that. The character animations, environment (its destructible!, weapon animations, etc are all extremely detailed. Back was such as day when graphics meant sacrifice of gameplay, and the vice versa. PlayStation 3 has proved that wrong with many games now. This is probably one of the best console graphics to date, heck I'd put it in one of the best graphics for any game category.
Game play is amazing. With a perfect cover system, which is 'icky' at first, but within an hour into the game it'll become natural. Same goes for the 'weight' of the weapons. This initially put me off from the game, but I came back to it and found much pleasure to be had. The multiplayer is where the game truly shines. Its faster and better than the Single Player (and I thought that wasn't possible). Warzone is a truly great way to play multiplayer. It gives you random objectives to complete together as a team. Instead of just 'Capture the flag' (Search and Retrieve) or Team Deathmatch (Bodycount)you get to do all of them without a loading screen! (or going back to the lobby!) The badges and class system to something to be pleased with. This is the successor to the famed 'Team Fortress'.
Here are the classes of online multiplayer:
The default multiplayer character is assigned when no primary badge is selected. A secondary badge may still be added. Riflemen can start with most weapons, except for the specialized ones.
Primary badge ability: Sets up an automated turret which targets the enemy.
Secondary badge ability: Repairs ammunition dispensers, mounted guns, and automated turrets.
Primary badge ability: Revives downed team mates.
Secondary badge ability: Throws a health pack, which can be picked up by other players.
Primary badge ability: Uses a cloaking suit to become near-invisible.
Secondary badge ability: Tags all on-screen enemy players with a hidden marker, which broadcasts their coordinates to team mates.
Primary badge ability: Dons heavy armour twice as strong as normal.
Secondary badge ability: Temporarily boosts running speed.
Primary badge ability: Throws a coloured smoke grenade, which serves as a spawn point.
Secondary badge ability: Requests air support from a sentry bot which targets the enemy.
Primary badge ability: Assumes the disguise of a randomly selected enemy player.
Secondary badge ability: Throws a sticky, proximity-activated C-4 charge.
Now to the Sound in the game. 7.2 channel audio, need I say more? Well, yes I do. The one flaw in the amazing sound recordings of Killzone 2 is the voice acting. It's not bad, but it could have been better. But scolar visari's Voice acting makes up for it. The best voice acting since last June. :D (Yes, David Hayter ;)) The explosion, bullets everything sounds the way it should. (this is a common feat among the next-gen games FYI)