I got my copy of the final retail yesterday. Unfortunately I was working on some other things and didnt get to spend hours with the game, but I didnt manage to check out some of it. It's worth mentioning that I did not download the demo and play it--I just have the beta disk (SP and MP) I received in December.
I fully expected to see some kind of installation with the final retail and unless it's doing something in the background that I didnt noitce--its not there. I'll check the gamedata file size and see how big it is but nothing was apparent and I didnt see anything pertaining to an install when I inspected the options menu.
In the actual SP game I didnt notice any changes in the graphical fidelity between the two, but really does there need to be? The game has been ploished, technically speaking, for months. It looks great and runs well.
I did notice that there are a few more additions to the environments like a new person standing here, groups of people repositioned for better presentation, some new dialog from NPCs and there are now new visual prompts during the introduction. For instance there are now RPGs streaking through the sky just pounding the ground--this might have been in the demo, but it wasnt in the beta. There is no denying that the game looks really good graphically speaking. I'm still not a huge fan of the art direction in the overall game--I personally would like some more variety throughout the entire experience.
Oh and during the dropship sequence in the very beginning of the game there is still a guy sitting next to you wearing a baseball hat that never moves along with everyone elses hair. This is despite the fact that you're traveling at a very high velocity in what is basically an open-topped space jeep dropping from hundreds (thousands?) of feet up in the air. Its definitely not a huge deal and means nothing in the overall game, but I still find it amusing to see that in a game that is as detailed as this one.
They appeared to have tweaked the controls a bit since the beta. There now appears to be a little more of a deadzone in the middle. What I mean is that if I slightly press the look-stick (lets say 2mm), the retical barely moves. when I say barely, I mean that it's a lot less than any other shooter that's out there. I did boost up the sensitivity on both th eY and X axis and this helped, bot only to a certain degree. I dont know how to explain it but it just felt a little sluggish. But this is also similar in my experience in the SP beta where it took me about 30 mins - 1 hour to get acclimated to the controls. I expect this to be no different.
I attempted to connect to the MP authentication servers and it errored out--MP is not up yet.
*Minor spoiler begins*
About 1/4 of the way through the game the environments changes pretty dramatically to a desert. I found this particular section of the game breathtaking. The dust being kicked up and swirling about, tattered fragments of cloth flapping in the wind, the whistling of the dry winds blowing into your face. Everything in Killzone, every underlying system in place, comes together to create this amazing moment for you. The subtle beauty slowly builds into this "wow" moment. All this in a rock solid frame rate.
*Minor spoiler ends*