Crowbar Collective has announced the release of all episodes of the original Half-Life remake on the Source engine, including all levels of the alien world, Xen. So far, access is only available in beta version.
In the latest update were added additional maps for the head of Interloper, the final battle with Nikhilant and Endgame, as well as fixed bugs at other levels of Xen. Now the developers want to gather feedback from players, fix the balance of battles and improve optimization.
To get into beta, you need to go to the properties of the game -> Beta testing and choose from the drop-down list of public-beta.
The full list of changes can be found in the official blog of the game. The release of the full version of Black Mesa is not yet mentioned.