Half-Life Deathmatch: Source is a classic multiplayer game that recreates the gameplay of the original multiplayer mode of Half-Life. Developed by Valve Software, it is a direct port of the original Deathmatch mode for Half-Life to the Source engine, which slightly improves the game flow by making controls more responsive and the connection more stable.

In Half-Life Deathmatch: Source, players battle each other in a free-for-all brawl, randomly spawned at different map points. To acquire any resource, players must scavenge the map for various caches containing weapons, ammo, health, and energy. The objective is to obtain the largest number of kills during the match by eliminating other players. In case of a draw, the player with the least number of deaths is the winner of the match. In addition to user-created content, there are 8 available maps for Half-Life Deathmatch: