[Update]: Black Mesa is finally being released! You can expect to see it arrive on March 5, 2020.
For those of you that might not know, Black Mesa is a fan re-imagining of the original Half-Life. It features improved visuals and sound design, new dialogue and voice acting, a variety of updates to some of the more annoying gameplay encounters, performance tweaks, and the list goes on for a while.
In short, Black Mesa is a very ambitious project, so it shouldn't come as much of a surprise to hear that the developers have now delayed the long-awaited release of Xen - the alien 'world' you visit in the later portions of Half-Life. According to the developers Xen has proven to be an enormous undertaking, and despite their best intentions things are taking a lot longer than expected. On the positive side, while Xen may have been pushed back, there will still be a significant update this December!
Once it arrives you can expect to see the addition of lens flares, numerous updates to dynamic lights, better ambient lighting, slightly changed textures, and perhaps most importantly of all, even further improvements to performance. Since trying to explain changes to lighting through words alone is a bit of a pointless venture, those of you that are interested in learning more should head over to the recent announcement post.
The final thing worth mentioning is that Black Mesa is currently 60% off as a part of the Steam Autumn Sale, bringing the price down to €8. Its currently in Early Access, but if you don't mind waiting a little while for the end-game to get finished its still well worth a look, especially if you're a fan of the original Half-Life.