This version comes with its own copy of the game (usually version 1.0004) and does not require a pre-installed copy of Shadow of Chernobyl.
There are two primary ways to install Secret Trails 2: using a (recommended for ease of use) or manual installation over a Vanilla game folder. Option 1: Standalone Repack (Easiest) Download Stalker: Shadow of Chernobyl - Secret ...
Once installed, you can play directly from the new installation directory. This version comes with its own copy of