Sites like Rampage offer direct downloads or torrents of the game. These are often "Non-Steam" versions, meaning you cannot play on official Valve servers. Critical Risks of Highly Compressed Files
While the official Steam installation requires downloading several gigabytes of data, a highly compressed "repack" can reduce the initial download size by 50% or more. Once downloaded, the user extracts or installs the files, which expand back to their original size on the hard drive. How Compression Works for CS: Source cs source compressed download