Those screens are very old. They go back to when? 2005-2006? (I remember the game being shown in 2005, and I think at least some of those screens go back to back then (I can confirm at least half of them going back to 2006).
Some things I'd like to say tho :
1) The point of the game ain't the gfx, they're not looking to make a "ZOMG GFX" game (otherwise they wouldn't be porting it to the 360 too), the point is really the story, the ambience, and possibly the lightning.
The videos were they were showing the world changing as time passed were goddamn gorgeous.
2) Saying that it's 4-cores optimized is like saying that Crysis is 4-cores optimized or that the Unreal-Engine is 4-cores optimized.
It will uses the 4-cores (possibly) but it won't be really "optimized" for it. It's not taking full advantages of it and is more of a "we may as well tap into that power since it's there, but we're not exactly refining that power into a beautiful gem and make it SHINE".
3) The game seems to focus on the atmosphere and the story. The atmosphere seems to revolve around light/shadows and stuff like that. Which is probably why one of the first thing we saw baaaaaack then were videos showing the world changing as time went on and ect. And damn it was beautiful.
I don't know if they modified it a lot, but what I do know is that they've been keeping it on the down low since then.
(Edit : In fact they did say that they modified several things, which should be a given since some of the textures (mainly the ground) weren't looking too good, or too generic. But they don't want to unveil it until they're close to release... Which either means they simply want to take their time (like they did with Max Payne before) or the game is god-awful ugly and they want to keep it a secret

)
So who know what the game looks like now, in 2008... Maybe it didn't change very much, that's entirely possible. And I kinda wish it was the case, I would rather have them increase the gfx lightly from back then (which would qualify as "medium/average" for today standards, with the exception of the lightning being great) and focus on adding more and more to the story/game.