A facelfit of a map from the leaked Half-Life 2 beta build. The original map was produced during a period where Valve were in the process of redesigning City 17 from a pulpy sci-fi city in the USA to a much more grounded Central European setting. Many prototype levels were made to explore this new style, and hall_01 seems to depict an indoor shopping centre.
The revamped version was intended to keep the same general elements, but expand on the shop fronts and make the area feel more lived-in and bustling.
Video showcase.