: Upon reaching the surface, you discover the U.S. military has been sent not to rescue you, but to silence all witnesses and "cleanse" the facility.
: Aliens immediately begin teleporting into the facility, killing staff. Gordon must fight through the crumbling complex to reach the surface for help. Black Mesa Definitive Edition Free Download v1.5.3
: During a routine experiment in Sector C, you insert an unstable crystal into an "Anti-Mass Spectrometer". This triggers a Resonance Cascade , a catastrophic event that rips open a rift between Earth and an alien dimension called Xen . : Upon reaching the surface, you discover the U
: Realizing the military won't help, surviving scientists task Gordon with reaching the Lambda Complex to teleport to Xen and stop the invasion at its source. : Upon reaching the surface
