From GameWatcher: “Black Mesa: Xen is coming out soon, if its latest beta test phase is anything to go by. Developers have pushed all of Xen and Gonarch’s Lair maps to the beta branch, which means there’s plenty more for us to run through.
This is the second stage of the game’s drawn-out testing phase, with the first one having only featured 3 maps, while the Xen/Gonarch beta brings this number up to 9 dedicated levels.”
Source: N4G PC Black Mesa: Xen Beta is now available