This announcement from the Black Mesa team informs us that a new December update is now in public beta testing for this authorized remake of the first Half-Life game (thanks RedEye9). This includes a bunch of technical enhancements, intended to bring the release version closer in line with their internal build. They say this will make the eventual completion of the project simpler, as the release of the Xen chapter will be more like a map release than a game update. They celebrate the news with a 75% off sale, and offer the following details:

We released an update for Black Mesa (currently on public beta) that adds real-time dynamic lights, lens flares, god rays, and a host of other features to the existing earthbound sections of the game. The goal of this update is to get the released version of the game as close to our internal build as possible. This way, the final Xen release can be closer to a simple map drop; with less potential for engine and code issues affecting players on their first time playing Xen. We are hoping to test the engine and solve all feature and performance problems before the real release, so that everyone can enjoy our definitive vision of the game without issues.

We are striving to make sure Xen is fun, well thought-out, and cohesive. Each chapter has its own theme and artstyle, and we are developing them in parallel to ensure they are all at the same high standard of quality. Xen, in its current form, is made up of 14 maps across these final 5 chapters, with each map alone being significantly larger than the originals. We are putting our full effort into completing Xen in a timely manner so that everyone can have the complete Black Mesa experience!