The full (almost) source engine conversion of Valve's unforgettable first entry in the Half Life universe has now been released. Follow the download link below to download it.
The game was synced for release at 8:48am New Mexico time, because that's exactly when Gordon Freeman arrived for work.
Black Mesa features everything from the original Half Life with reimagined visuals, up until the end of the Lambda Core segment. The Xen portion of the game will be released later and is said to be almost an entire game in its own right due to additions from the development team. This freely available mod only requires you to own one source engine game on Steam in order to play.
Enjoy guys. This one's been eight years in the making. Don't rush through it too fast.