Half-Life: Source 2004 - C++ Source Code
Please read before download. I have found December 2004 source code. It was the first release of Half-Life 2 source code. I have removed all stuff from Half-Life 2 and added the stuff from Half-Life: Source. You can download and modify the source code. Wish you a luck.
Download link.
https://drive.google.com/uc?id=1FZrwLLFOKEIjooLohVj-76bc3oX2e3hm&export=download
How To Install.
Download "Game.rar" archive and open it. You will see two folders - "C++" and "Game". For those people who would like just to play the mod, open "Game" folder in archive and extract "Half-Life Source" for example, to your Desktop. Then go to extracted folder and you will see "Half-Life Source.exe". Double left-click on it and play. For those people who would like to modify the source code, open "C++" folder and extract "src_mod" folder, for example, to your Desktop. In the "src_mod" you will find "Game_SDK.sln" file. You can compile it only with Microsoft Visual Studio .NET 2003. Good luck.