Half-Life 2: Deathmatch is a multiplayer first-person shooter video game developed by Valve. Released on Steam on November 30, 2004, it uses many of the assets from Half-Life 2 and its Source engine. It features new levels, optimized for multiplayer arena play, and a few new weapons. Also included are portions of the game's source code, which were the basis for many early Source-based multiplayer modifications. The game is the successor to the popular multiplayer component of the original Half-Life, but is offered as a separate product from Half-Life 2. Deathmatch, like Half-Life's multiplayer, does not develop any part of the plot or story of the Half-Life series.

Steam is a video game digital distribution service and storefront developed by Valve Corporation. It was launched as a software client in September 2003 to provide game updates automatically for Valve's games, and expanded to distributing third-party titles in late 2005. Steam offers various features, like game server matchmaking with Valve Anti-Cheat measures, social networking, and game streaming services. Steam client's functions include game update automation, cloud storage for game progress, and community features such as direct messaging, in-game overlay functions and a virtual collectable marketplace.