SteamLink is an effort to run Half-Life: Uplink, Half-Life's single-player demo campaign from 1998, in Steam as easily as
possible, while leaving it as true to the original demo as possible. No in-game
content has been modified, and the "loading" and menu backgrounds are taken directly from the original Uplink, as opposed
to the generic Half-Life screens in Steam.
Simply download and run the installer. The installer will determine your Steam installation directory, and place files in the necessary directory. After the installer finishes, restart Steam, and "Half-Life: Uplink" should appear as a "Third party mod". In addition, a "SteamLink" Start Menu group will be created for direct access to Half-Life: Uplink.
Download Half-Life through Steam for Linux / OS X, and run it at least once.
Download and extract the zip archive.
Run install.sh, which will determine the Half-Life for Steam install path, and copy the necessary files to the correct place.
$ sh steamlink/install.sh
After the installer finishes, restart Steam, and "Half-Life: Uplink" should appear as a "Third party mod". The installer will also create a shell launch script, and symlink it to ~/bin/steamlink.
If ~/bin is in your $PATH, you may execute it directly.
Once installed, the extracted zip contents are not needed, and may be removed.
Notes / Limitations
Of course, the entire point of SteamLink is to play Half-Life: Uplink from within Steam, which means using the current Half-Life GoldSrc engine. The major benefit is better current hardware/Windows support. The downside is, for whatever reason, Valve decided to remove strafe leaning from GoldSrc a long time ago. You win some, you lose some.