Kikizo:

Kikizo: The atmosphere in the original Half-Life 2 game was this dystopian society, very bleak, and some interesting progress is made towards the end of the game, but how would you describe the changing atmosphere in the new episodes?

Lombardi: So as we progress through the trilogy, we move from City 17, post Half-Life 2 where things are more grim and whatnot, and Alyx and Gordon have sort of moved towards their journey beyond the city at the close of Episode One. In Episode Two, you're out of City 17 and you won't be going back. At least not for a while. [Smiles]. And you're in this very expansive forest, that opens up the gameplay to a broader scale. The hunter - the new creature that's been introduced - is designed to take advantage of that; he's much faster and he can traverse both the landscape as well as indoor areas. And we're also providing a new vehicle that you'll be spending a lot of time in, moving quickly through that forest, fighting large-scale battles against striders and packs of hunters etcetera.

Be sure to check out the aforementioned interview in full.