The fan-made Half-Life remake Black Mesa took another step toward completion over the weekend with the release of a Xen engine patch that fixes a number of issues including freezing and crashes on Radeon 300, 400, and 500 series video cards.
"We will probably do one more 'Engine' release just before we drop Xen, in order to make sure that everything is running smoothly on everyone's machines," developer Crowbar Collective wrote. "We want the Xen release to be as close to a simple content release as possible."
Black Mesa is largely a faithful recreation of the groundbreaking FPS Half-Life, but it makes some changes as well, shortening or otherwise editing some levels while expanding others in ways that the old GoldSrc engine wasn't capable of. The one thing it's lacking, despite being in development since at least 2005 (seriously, Black Mesa: Source, as it was known then, won ModDB's "Mod of 2005" award), is Half-Life's concluding Xen location.
And that's perfectly fine by me: Gordon Freeman would've been better served with a Poochie-style sendoff than the ugly, tedious slog through Xen he ultimately got stuck with, as far as I'm concerned. But that's how Half-Life ends, and so—eventually—that's how Black Mesa will end, too.
There's no word on when Xen will actually be added to the game and even if there was I'd strongly suggest taking it with a handful of salt: The rollout has already been delayed twice, most recently in November 2017, just ahead of a "do-or-die deadline" that had been set for December. (Obviously, it did not.) There are, however, patch notes and a list of known issues available for perusal on Steam.