Named Game of the Year by over 50 publications, Valve's début title blends action and adventure with award-winning technology to create a frighteningly realistic world where players must think to survive. Also includes an exciting multiplayer mode that allows you to play against friends and enemies around the world.
Original VMF map files for HL Source that can be used in goldsource HL1. just open the maps with a goldsource map editor like Jackhammer. However, it won't be perfect in all areas. There will still be some missing textures and missing brush work from the ported map, like in the screenshot.
yippie!!!!!
though they require a lot of modifications to make them work in hl1 goldsrc