I cant see anything but the outline of the city and a small part of the flag at the end, is that all there is or is there something wrong with my eyes ... or something ...
Other than that, I'm exited, Fallout 3 kept me busy for so long.
For you Andar, here is a better picture of what you see in the trailer, compare with the better picture of the flag I posted, comfirms it really. Thats the NCR.

Found out some info;
The game is set 39 years after the events of FO2 and 3 years after FO3. The player plays a couriar, I assume someone who delivers messages across the wastes. With the NCR there is another faction called Ceaser's legion, this faction was going to be in the original FO3 before it was cancelled.
Karma is back, but there is also reputation like in FO2. To get an idea of this, in FO2 you could join the slavers, you got a mark on your forehead, and I walked into a settlement and with in a matter of seconds, combat intiated and my character was shot apart.
Also hitting an enemy with a close combat weapon will have unquie animations. And also there is a hardcore mode, you need to drink, ammo has weight, and healing isn't instantanous like FO3 where you slept for an hour, it's going to be more like Fo1 and 2 with added water.