Several of the tracks are composed of licensed or stock "samples", a notable example being the Methods of Mayhem Industrial Toolkit sample pack by Sony that was used by Kelly Bailey for most of the soundtrack. Due to the sample pack being publicly available (at the time), some of the same samples can often be heard in other games or even movies. An example is the drumbeat sample used in Hard Technology Rock, which can also be heard in the track Crush from the Command & Conquer: Red Alert soundtrack.
|1||Adrenaline Horror||"We've Got Hostiles": when Gordon encounters the first Osprey and a squad of HECU soldiers.|
|2||Vague Voices||Black Mesa Inbound: during the tram ride to Sector C.|
|3||Klaxon Beat||Anomalous Materials: when Gordon acquires the HEV Suit.|
|4||Space Ocean||Unforeseen Consequences: as Gordon wakes up after the Resonance Cascade.|
|5||Cavern Ambience||Unforeseen Consequences: while descending on a platform as Headcrabs come out of a vent above.|
|6||Apprehensive Short||Unforeseen Consequences: when seeing the Zombie in the dark room seated in front of a flashing monitor.
Office Complex: while exiting the elevator and seeing a live wire blocking the path.
|7||Bass String Short||Office Complex: in a room with a boarded up exit and Headcrabs falling from the roof.
Apprehension: upon entering the freezer area.
|8||Hurricane Strings||Office Complex: within the freezer area.|
|9||Diabolical Adrenaline Guitar||"We've Got Hostiles": immediately after the first encounter with the HECU.|
|10||Valve Theme (Extended)||Surface Tension: as Gordon crosses the cliffside area.|
|11||Nepal Monastery||Blast Pit: when entering the Silo and hearing the Tentacles for the first time.
Surface Tension: when nearing the tentacle in the sand.
|12||Alien Shock||Power Up: upon seeing the first Gargantua.
Surface Tension: when encountering the Gargantua in the parking garage.
|13||Sirens In The Distance||On A Rail: when Gordon descends into the tunnels.|
|14||Nuclear Mission Jam||Questionable Ethics: when picking up the Tau Cannon.|
|15||Scared Confusion Short||Apprehension: while witnessing the first Ichthyosaur, and while seeing a security guard get shot by Black Ops.|
|16||Drums and Riffs||On A Rail: right after launching the Rocket.|
|17||Hard Technology Rock||"Forget About Freeman!": during the battle between the Alien Grunts and HECU soldiers.|
|18||Steam In The Pipes||Lambda Core: when opening the portal to Xen.|
|19||Electric Guitar Ambiance||Surface Tension: in the area with Laser Tripmines and a Sniper.|
|20||Dimensionless Deepness||Xen: in the first teleporter room leading to Gonarch's lair.|
|21||Military Precision||Residue Processing: after meeting up with a security guard.|
|22||Jungle Drums||Gonarch's Lair: when Gordon fights the Gonarch.|
|23||Traveling Through Limbo||Nihilanth: while fighting the Nihilanth.|
|24||Credits / Closing Theme||Endgame: during the credits.|
|25||Threatening Short||Xen: after arriving Xen; and at the portal leading to the Nihilanth's chamber.|
|26||Dark Piano Short||Questionable Ethics: when Gordon finds an Alien Grunt confined in a glass tube.
Surface Tension: in the core of the missile storage room.
|27||Sharp Fear Short||Power Up: after Gordon kills the Gargantua.|
Behind the scenes
The tracks Vague Voices, Steam In The Pipes, Traveling Through Limbo, Dimensionless Deepness, and Threatening Short all have the name "
Prospero" in the game files, implying they were originally to be used in one of Valve's canceled games, Prospero.
In several pre-release videos of Half-Life, a different version of Diabolical Adrenaline Guitar can be heard. It was likely changed in Summer 1998, as the old version can be heard in the E3 1998 Gruntfight video but is not present in Half-Life: Day One.
|Soundtracks||Half-Life • Opposing Force • Blue Shift • Half-Life 2 • Episode One • Episode Two • Half-Life: Alyx • Portal • Portal 2|
|Songs||Exile Vilify • Cara Mia Addio! • Still Alive • Want You Gone|
|Other||Half-Life: Further Data • Mishaps in the Reactor Chamber|