The small section of gameplay they showed was in Nepal City, the same area seen in recent screen shots. The city is about 1/4 of the way through the game and its in the midst of civil war with ravaged buildings and burning vehicles. Nathan tries to sneak into the city by pretending to be a reporter, but when the guards get suspicious, he busts through the gate.
The beginning of the demo opens with a bunch of soldiers searching for Nathan, only to soon be run over by a runaway bus. The wrecked bus blocks the street, forcing Nathan to climb across some crumbling buildings, using shop signs and street lights to traverse and narrowly avoids impaling himself on some exposed rebar.
The developers then used this opportunity to show off some of the games expanded stealth gameplay what theyre calling action-stealth since they dont want the pacing to get slowed down. They hung just below one guy waiting for the right moment to grab and toss him off the side of a building. Then back on ground level they snuck up behind another soldier standing in a doorway, grabbed him and knocked him out on the brick wall. Stealth kills can apparently net you more grenades or better weapons in the right situations, and using cover keeps you safe from soldiers line of sight as well as bullets.
The other big gameplay feature that they talked about but didnt really show is traversal gunplay which basically means that Drake can now shoot back when hes climbing on walls. They even talked about being able to hang from a sign on the side of a building, using it for cover, and peeking out over the top to fire.
Theyre aiming for a much broader range of enemies and AI behaviors. Some enemies carry big shields, which you can also pick up for portable cover if you take them down. Soldiers will also hunt for Nathan and follow him to his last seen location if you try to run away, sounding like something youd expect from Metal Gear or Assassins Creed.
Unknown to many, one of Naughty Dogs teams actually works full-time on tech for PS3 developers to get the most out of the system, giving the developer a bit of an advantage. They estimate that in the first Uncharted, they were only utilizing the SPUs to about 30% but now theyre actually running them at 100% which gives them a lot more processing power to work with.
In the first game, they used two different character models for cut-scenes and gameplay, but now they have the same character model for both. They also proved to us that the scene in the VGA trailer was indeed real time, showing us the scene again and moving the camera around inside and outside of the train in 3D space.
There are more interactive items in the environment, more animations for Drake for different situations (walking across the moving train, etc.), and new shaders for things like snow, ice, and fur (Nathan will be getting a coat to keep him warm). It sounds like they want the snow and ice to be just as impressive as the water was in the first game and theyre working on effects for footprints, sparkling, and translucence.
The art team is obsessively gathering references for all the different environments and thinking through back-stories for the use of every room in the game. One artist even ran to a house that caught on fire and asked the owner if he could take pictures for reference.