I've seen a lot of people compare Killzone 2 to Gears of War 2, most of them have very little technical knowledge and have a huge bias towards one side. Although it doesn't take a genius to see select the better looking image from 2 screenshots, it does take a little technical knowledge to know how it looks that good, why it looks that good, and why sometimes the inferior looking image may actually be technologically superior. If you already think that Killzone 2 is the best thing since sliced bread or that Gears of War is the product of Einstein's immortal twin, then great, just go ahead and skip through this thread. However, if you would actually like to see an unbias comparison and are interested in learning a thing or two, then I feel free to continue reading! I hope people enjoy this thread, regardless of which game they think looks better.

Let me begin by saying that as far as consoles go, I favor the Xbox 360 due to Xbox Live. However, I also enjoy my Playstation 3 greatly. Feel free to look at my posting history, I've tried my hardest to not let my personal preferences get in the way of technical discussions. That said, lets begin! I'll try to keep this as simple as possible for those that don't have a deep understanding of technology.

--Environment and art style--

First of all, let me begin by telling you what most of you have already guessed: If you take a stranger off the street and make them play both GoW2 and Killzone 2, most of them will think Killzone 2 looks better. Now, lets take GoW2 and run it on the Killzone engine and take Killzone 2 and run it on the GoW2 engine. The result? Killzone 2 would still look better than Gears of War 2 to most people. Before we even talk about technology, Killzone 2 and GoW2 have a completely different art style. You could argue they are both grunge games, but they go about it in different ways. I don't mean to discredit Guerilla Games, but they took the easy route. Killzone 2 looks this good because it is easier to make this type of game look good. It is a game with very little organic and natural figures. I bet they have at least one in there, but for the most part, the game has no trees. The game also lacks vegetation and features very little landscape. Why is this important? Simple, organic content is very hard to make look good and takes a lot of power. Trees in particular require a lot of power to render properly. Lets take a look at these pictures: 

Note: I included links to 720P pictures. I didn't include them in here because VGChartz seems to cut them off. I also didn't resize them because resizing pictures introduces artificial AA which benefits 1 of these games more than the other.

Killzone 2: http://ps3media.ign.com/ps3/image/article/949/949161/killzone-2-20090129014059684.jpg

Gears 2 : http://www.gamershell.com/static/screenshots/12987/356480_full.jpg

GoW2: Now, before you start sending me hate mail, I know that I cherry picked an example of a good Killzone 2 pic and a bad GoW2 one. Why does the GoW2 pic look worse? First of, notice the trees. Unlike in Killzone 2, they exist. Also, the buildings are growing organic matter and mold. The trees require quite a lot of power to render and conflict with the theme of the game.

Killzone 2: Count how much organic matter you see. Count the number of round edges. Not many, huh? This looks good, but it is just plain geometry. Geometry is very easy to render and take up very little space in memory. Also, notice the similar color scheme. The same textures are being used over and over, and although they look different, it is a result of them stacking multiple textures on top of each other.

Now, lets see what Gears of War 2 would look like if it didn't have so much organic matter and features industrial levels similar to those that populate Killzone 2.

http://www.gamershell.com/static/screenshots/12987/366502_full.jpg

http://www.gamershell.com/static/screenshots/12987/366504_full.jpg

They look pretty good, and even then, they still have organic matter and bright scenes. Although I think Killzone 2 does have better shadows, aside from it being an art direction choice, it makes parts of the game easier to render since they can use lower resolution textures and hide it with darkness.

Now, lets flip things again. Killzone 2 with organic matter. Sadly, I was only able to find 2 screenshots after searching online for 30 minutes.

http://ps3media.ign.com/ps3/image/article/949/949161/killzone-2-20090129014103325.jpg

http://ps3media.ign.com/ps3/image/article/935/935547/killzone-2-20081203111746978.jpg

As you can see, the organic matter does not look so great. As you introduce bumps, round objects, and surfaces into a game, the power requirement to make it look good jumps up. It is very simple to make square edges look good but round edges take more power. Now, I've played the Killzone 2 demo and although there are some broken surfaces with rough edges that do look pretty good, they are pretty minimal throughout the demo.

If killzone 2 were running on its engine on the PS3 and the exact same game on Epic's engine on the Xbox 360, I have no doubt that Killzone 2 would look better on the PS3. However, the difference would not be by much. Due to its smaller OS, the Xbox 360 has more memory available to it than Killzone 2. Killzone 2 on the PS3 would probably have a bit more going on on the screen at the same time but the Xbox 360 version would have higher resolution textures. GoWII on the PS3 however would be identical to the Xbox 360 version with slightly blurrier textures. Granted, Killzone 2 on the 360 would probably take up 2 discs unless procedural synthesis was used (which would require all the art to be remade from scratch). With procedural synthesis, developers can fit Gigabytes of information in a few hundred megabytes. There is a 96KB game(.kkrieger) that fits 200MB of data into it due to its use of procedural synthesis. 

--Bottom line--

Yes, Killzone 2 does have a very advanced engine and it does make great use of the Cell processor, however, it mainly looks the way it does because of the art style. Not only did it take the safe path, but it also (in my opinion) selected a superior color palette. Based on what I saw from the demo and other Xbox 360 games, I think that it *can* be done on the Xbox 360, it would just take as long as the PS3 version. If they use procedural synthesis, it would take longer. If they don't, it would have to ship on multiple DVDs. 

I know this won't end the Killzone 2 exaggeration. The game looks very good and is my pick for best looking game out there, but it is not as drastic as people make it out to be. If I missed a screenshot which demonstrates Killzone 2 with trees or organic matter, please post it, I am very interested in seeing it. However, don't post sub 720P images and animations of Killzone 2/GoWII because they are pointless. When you resize the screenshot, it gains artificial AA which makes them look 2X better than they are.

If you disagree with me or have some feedback, I'm more than happy to hear it. However, if you're posting anything else besides your opinion, such as technological reasoning for something, please have facts to back it up. 

EDIT: I also wanted to mention that although I did work in the game industry for a very short while, it was mainly programming physics. Everything that I've concluded here comes from my short time in the industry, fun projects I've worked on, technical documents I've read, and friends that program games for a living. 

@Ascended_Saiyan3 Post 1

Nothing that you stated is news to me, I knew those things prior to writing my initial analysis. Also, what you said about Killzone 2 is not true, there are parts where GG's tricks can be seen because of ill-placed mirrors and other slight design choices. Killzone 2 has a lot of very impressive features, however, textures aren't one of them. Don't get me wrong, they are impressive, but a few select games outdo it.

@Ascended_Saiyan3 Post 2

Uncharted is indeed an amazing, and some parts are more sophisticated than Gears of War 2, but not nearly as much as you make it seem. Uncharted does some things better and GoWII does some things better. However, overall, Gears of War 2 is technologically superior to Uncharted in many ways. Btw, that paper was released before GoWII was released and if you understand the contents of it, it's not something that one would use against GoWII.

A few games outdo Killzone 2 in textures such as... ?

Anyway, what makes Killzone 2 REALLY inpressive is that it does EVERYTHING well!  It doesn't compromise because the engine or  console or both doesn't have the power to make it happen.  Other games sacrifice in many areas to make one particular area look impressive.  Even Crysis sacrificed animations, 7.1 discrete audio, character models, gun models, A.I., characters on screen, etc. in order to have the HDR lighting, parallax mapping, geometry, draw distance, particle effects, etc to be as impressive as they were.  Crysis physic engine was HIGHLY impressive...until now.  You should know this.

Uncharted is amazing and STILL unbeaten, TECHNICALLY, from the X360 game engine perspective.  Why don't you present the technical post-mortem of Gears 2 like I did for Uncharted so EVERYONE (that can read it) will see what I mean?  So please explain how Gears 2 is superior to Uncharted technically.  I know it's not in textures, character models, animations, shadows, HDR lighting, geometry, A.I., or audio.  I'm not making it SEEM like Uncharted is technically superior to Gears 2.  I presented the technical documentation already.  I'm just waiting for you to present the same for Gears 2.