Anomalous Materials
You were Gordon Freeman, a scientist arriving for work at the Black Mesa Research Facility. Wearing your protective HEV suit, you pushed a strange sample into an experimental beam. The test triggered a resonance cascade, tearing open a connection to the alien borderworld Xen. You survived the blast, but the laboratories collapsed around you and alien creatures began appearing throughout the complex.
We’ve Got Hostiles
You searched for a route to the surface while scientists and security guards struggled to survive. The arriving soldiers seemed to promise rescue until you saw them killing staff. Their mission included silencing witnesses. Driven underground by military fire, you headed toward the Lambda Complex, where surviving researchers might close the breach. A silent man in a suit repeatedly watched your progress.
On A Rail
You crossed the underground railway to launch a satellite rocket requested by the Lambda team. Soldiers had stopped the launch; you fought through their positions and sent it into orbit yourself. Later, marines captured you and dumped you in a trash compactor. You woke before its walls closed and escaped through Black Mesa’s waste systems, continuing toward the scientists who still needed you.
Lambda Core
You reached Lambda after the military withdrew. You flooded and crossed the reactor to reach the surviving scientists. They explained that a powerful being on Xen was holding the breach open and that you had to kill it. You collected a long jump module and reached their teleporter. You defended the scientist operating the machinery, then jumped through the portal.
Xen
You landed among Xen’s floating islands, where dead researchers showed that Black Mesa had sent expeditions before you. You crossed the borderworld and fought the huge Gonarch. Beyond it lay alien installations and the route to the Nihilanth, the being sustaining the breach. You destroyed its healing crystals and attacked its exposed brain. Its death ended the battle in a blinding eruption.
The OfferThe ending
You emerged before the suited observer, the G-Man, who had taken your weapons. He praised your survival and offered work for his unseen employers. Your answer determined the ending. Acceptance meant entering his service through a portal, with your next assignment left unknown. Refusal meant being sent unarmed against an overwhelming alien force. You had defeated the Nihilanth; what followed depended on your choice.
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Written by an AI model from the game's wikis, and checked against them part by part by another before it was put here.