The most famous way to play classic Half-Life deathmatch without Steam is through the (originally the Steamless CS Project). This community-run master server mimics the original World Opponent Network (WON) that Valve shut down in 2004.
: This version is a "time capsule"—it reflects the game as it was in 2004-2005, before many of the modern Steam updates broke certain features. Half-Life Wiki 2. The Community "WON2" Project For those looking to avoid Steam entirely and play the Half-Life Deathmatch (not the Source version), the project is a fan-made network. Steam Community What it is half life deathmatch source download free non steam
Archival versions like the 2006 source files on ModDB are used by modders to fix bugs introduced in later official updates. The most famous way to play classic Half-Life