Half-Life-Blast Pit

Note:Sorry if the audio goes out of sync later on.

Gordon enters an abandoned, largely sealed-off area of Black Mesa dating back to its earlier days as a missile complex, full of mothballed machinery and now used as a dumping ground for toxic waste from the rest of the facility, where the HECU soldiers have yet to get a good foothold because of the overwhelming amount of aliens in the area.
Arriving at a rocket engine test silo Gordon faces a deadly new foe, the Tentacle; however, after reactivating the fuel, power, and oxygen lines, Gordon is able to kill it by using the rocket engine to incinerate it, and finds a way out through the meters-long dirt tunnel dug by the Tentacle.