For the first two parts of my playthrough of Black Mesa Source, please checkout the First Impressions review.
In this I pickup right where I left off with Gordon Freeman just realizing the full extent of the carnage that has taken place in the Black Mesa facility. Not long after we continue out adventure, Gordon finds himself hundreds of feet above a small river of sludge and Freeman must jump across the cargo box containers. After traversing the damaged lined of the black mesa facility, we're into the offices.
The scientists are falling victims to the same monsters that you're surviving thanks to the hazard suit. Black Mesa becomes more dangerous as the turrets and other security systems seem to think anything and anyone that moves are a threat.
Things are looking up though as a major change from the original Half-Life occurs when Gordon gets hold of the Colt Python ( magnum ) after a short while from a security guards weapons stash. Perhaps I can survive Black Mesa after all.