Deathmatch Classic

Deathmatch Classic or DMC is a multiplayer mod for Half-Life. It was released as a free download concurrently with the 1.1.0.7 patch of the game on June 11, 2000. It now costs $4.99 USD in the Steam store.

DMC and Quake
DMC was conceived by Valve as a tribute to id Software, and is essentially a remake of the multiplayer component of id's  Quake.

The original release included five maps converted from Quake. The gameplay is similar to Quake Deathmatch, with essentially the same weapons (except the one for mêlée combat, which is Half-Life's trademark crowbar instead of the original axe). DMC also imitates Quake's physics, which allows an advanced player to gain a lot of extra speed or jump very high by using a number of movement skills such as bunny hopping and rocket jumping.

Gameplay
The default game speed in DMC is somewhat slower than in Quake. The weapons scale from the basic shotgun to the rocket launcher and the Lightning Gun, a powerful directed energy weapon. Three kinds of bonuses are scattered over the maps, which give the player a temporary special power: "quad damage", "invulnerability", and the "ring of shadows" which turns the player into a ghostly, almost invisible figure.

The DMC community
Not enjoying widespread popularity like the team-oriented Half-Life mods, Counter-Strike and Day of Defeat, DMC has found its fan base particularly among nostalgic deathmatch veterans. Further Quake maps were converted for DMC by fans, and original new maps designed. Many of the DMC servers, DMC Central and Free Fall DMC, offer a further modification of the game titled DMC Pro. It includes a Quake-style sound pack, custom maps, capture the flag and alternative versions of the default maps where the two most powerful weapons are more easily available, and there is a plenty of ammo for them. DMC Pro is characterized by extremely hectic action, the rocket launcher being practically the only weapon used.

DMC:Source
In October 2004, an independent mod developer announced that he was starting to work on DMC:Source, a conversion of Deathmatch Classic to the Source engine. Several people teamed up with him on this project, but it was eventually suspended. Valve Software have not announced any plans of their own regarding the conversion of DMC to Source.