: 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 .
While the main plot remains the same, the (the final major update, also known as version 1.5) adds several story-enhancing features:
: 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, you discover the U.S. military has been sent not to rescue you, but to silence all witnesses and "cleanse" the facility.