Half-Life Deathmatch: Source is a recreation of the first multiplayer game set in the Half-Life universe. Features all the classic weapons and most-played maps, now running on the Source engine.
During the 2013 Steampipe update for Half-Life: Source, the HD pack from Half-Life 1 was added to the game and is a toggle in the options menu. However; there were some problems with the integration that still have not been fixed as of 2018. Some weapon sounds do not work, specifically with the pistol and the assault rifle. This fix/patch (which I did not make and is taken from a github user) fixes those sound problems with the HL:S HD Pack.
Half-Life Source High Definition Pack sound fix. Not tested in Half-Life Deathmatch: Source but may still work assuming that the HD pack and sound bug are also present in death match source. See readme in file for install instructions.