After returning to the surface, Gordon must fight through hordes of Marines and Aliens who are locked in combat with each other. Gordon's destination is the Lambda Complex on the far side of the facility. The chapter's most famous location is the Black Mesa Hydro-Electric Power Facility, more commonly known as "The Dam". Surface Tension is the twelfth chapter of Half-Life. The chapter features expansive outdoor sections and large-scale firefights as the primary backdrop. In addition to Marines, the player also encounters several Apache Gunships and Tanks that require much heavier firepower to destroy. Several new environmental hazards are introduced, such as minefields and jump platforms.
