We reported back in November last year that Black Mesa, the 12 year old project to update Half-Life 1, was finally nearing it's final hurdle, adding Xen to the game. That was later pushed back to December last year, and then pushed back further again - but the good news is that finally the first two chapters of the game are now finally available for the public to play.
The story of the development of the game has been a rocky one - the developers behind the game, Crowbar Collective, have been trying to add Xen to the game for the majority of that 12 year development cycle, although the game has gone through many engine updates and changes, this is the one element that has always been missing - the rest of the levels being playable for many years now.
The two updated chapters let players walk through Xen and Gonarch's Layer, with a total of nine maps to play. It's a massive expansion on the original Half-Life level to a full sub-game all of it's own, which accounts for much of the delay, and frankly it's worth the wait, it looks phenomenal.
More levels from the Xen section of the game will be coming to the development branch soon too. If you want to give it these updates an early try, you'll need to own the game on Steam, which is conveniently on sale currently, then go into the game's properties menu and and go to the beta tab.
The team have stated they'll be going a little quiet as they push for the final launch. Stay tuned to GameFront for more on this as we learn it.