Frijoles wrote on Jun 27, 2012, 15:28: :40 seconds, we see Alyx running on a light bridge. I'm guessing that's what the bridges were in E2. I forgot about those and thought for a moment that we were seeing a sneak peak of something. Still, I don't recall cinematics in HL2.
I think that's a shot from Episode 1 and it's probably from a trailer.