Mysterious Vortigaunt image - Xen Assault mod for Half-Life

Story: After entering the portal at the end of Half-Life you are frozen by the Gman. Many years pass and humans build and occupy a city called Xentopia on Xen. Xen Life forms are captured and held in prison. While citizens of Xentopia continue to live in prosperity, a prison guard finds a blue eyed vortigaunt near the prison. They capture it and put it into a cell immediately. After a few hours later the unique Vortigaunt proceeds to overtake the prison and free all Xen life forms. Xen life forms start to terrorize the city to take their home back. After few weeks later when the city is at the edge of chaos Gman wakes up his secret weapon. Gordon Freeman.