It's an upcomming Star Wars game that is expected to be released roughly at the time of the new Xbox at the end of 2012, and so far has been presented on a very powerful PC on E3 in June. And the graphics look really amazing. What I assumed to be prerendered CGI cutscenes of current standard quality, was actually in-game graphics, which is quite impressive.
It's apparently about two bounty hunters on Corruscant going down to level 1313, one thousand levels below the "surface" or roofs of the planet-spanning city. Some people coplained that it doesn't look or feel like Star Wars at all, but I think it actually does quite a lot. It's just a part of Star Wars that rarely has been shown in a visual medium so far. If you are familiar with Black Sun, Nar Shaddar, Kessel, and such, I really think it fits right in.
So far, I don't know what to make of it. Lots of people describe it as Star Wars Uncharted, but I never played those games. Interesting concept from what I can tell, but so was Force Unleashed, which was a total dud. And you have to be careful about any game that is marketed as "mature", which usually means "immature obsession with gore and boobies".
Edit: A yes, you might be interested in seeing the trailers in question.
Trailer
Demo