Half-Life 2: Episode One soundtrack
Using an appropriate program, it is possible to extract all audio tracks heard in-game from the "
ep1_pak_dir.vpk" archive file. On September 24, 2014, the soundtrack was made available as free DLC to all owners of the game on Steam.
 Track listing
* = not present on the Orange Box Original Soundtrack CD.
|Orange Box OST #||Game #||Track title||Filename||Time||Level location||Comments|
|*||01||Eine Kleiner Elevatormuzik||
||1:18||Undue Alarm: When looking over the ledge in the Citadel where Alyx comments "I had no idea," before encountering the Stalkers and the Rollermines.||The title references Mozart's "Eine kleine Nachtmusik," Dr. Isaac Kleiner, and Muzak.|
||1:54||Undue Alarm: When entering the room with the shaft full of Advisor pods.|
||1:56||Undue Alarm: When getting on the large glass elevator.||Also appears in Half-Life (under the name "Steam in the Pipes") and Half-Life 2.|
||4:38||Direct Intervention: When entering the Citadel Core.|
|*||05||Darkness at Noon||
||0:56||Lowlife: When first entering the vents where Alyx comments on being "blind as a bat."|
||1:18||Lowlife: During the first large fight with Zombines in the tunnels.||This track was created as the introductory cue for a new enemy, the Zombine.|
||3:07||Lowlife: After the lights by the elevator go out and Alyx comments on the sparking wire.||Also appears as the first song in the fourth Half-Life 2: Episode One launch teaser.|
||2:00||Lowlife: After Alyx says "here comes trouble" at the start of the zombie battle.||Appears as the second song in the fourth Half-Life 2: Episode One launch teaser.|
||1:39||Urban Flight: When Alyx mans the turret after killing the Antlion Guard.||This track is used in the third Half-Life 2: Episode One launch teaser.|
|*||10||What Kind of Hospital Is This?||
||3:05||Urban Flight: When Alyx gets a shotgun before entering the hall of zombies.||Also used in the first Half-Life 2: Episode One launch teaser.|
||2:50||Exit 17: When the Strider first appears.||"Penultimatum" is a portmanteau of the words "penultimate" and "ultimatum." This track is used in the second Half-Life 2: Episode One launch teaser.|