This is a press-version build of Half-Life Opposing Force from Gearbox Software, which was provided back in the days to several game media resources for reviews.
The original disk has beed sold by former IGN employee at e-auction website to Alan "Magic Nipples" Decker. Later the contents of the disc became public.
This build contains several changes compared to retail version.

This build only works above installed Half-Life v1.0.1.3 (WON), so Steam version is not supported.

Thanks to Vect0R for provided archive.