Zero Storyline 

This is a transmission to anyone still alive in the Black Mesa Facility. As I'm sure most of you will know, the facilities big "experiment" was a disastrous failure. It seems a portal to a world known only as Xen has been opened, and we've gathered the inhabitants of this world are not to pleased at us finding them. It also turns out our facility was littered with government spies, so we're now going to be swept under the carpet as part of the cleanup operation.

 The original plan of trying to rescue those in the levels below us has been aborted. So far everyone who was a part of this rescue team has failed to return. The new plan is to gain access to the upper levels. By doing so we should be able to find the remainder of our team, whom we hope are still alive.

 The route to the Lambda complex will not be an easy one, but remaining in the area will mean you'll be facing almost certain death. The Xen creatures continue to destroy the structure of the facility and are transporting more alien soldiers in the facility at an alarming rate.

 As you already know a high military presence has been detected in the upper levels of the facility. While these soldiers are highly trained, they can overcome if you attack in large numbers. The Black Operatives however are a different story. To over these you will need to use the brains that got you this job in the first place.

 It is vital you are successful in contacting the Lambda team. They will play a key role in helping at least some of the staff escape. It will also be vital for exposing the corruption of the government and its attempt at covering up a vital scientific discovery.

Good luck my friends, we're counting on you!