Now this is an interesting idea, though I don’t think it worths the effort. This would only fit into the surface area of WHG, however there the general situation is that the military is in control of the surface, and Gordon’s only option is to quickly find a way back to the underground.
– On my part, I think the intro credits, and chapter names’ fonts should be updated a bit also, I would generally make them alike with the ones in Half-Life. It would give a nice connection… in my opinion.