Black Mesa's ambitious expansion to Half-Life has reached the last stretch. After a technical beta in June, which tested a few maps, Black Mesa: Xen's first two chapters are now available in the public beta branch. Xen and Gonarch's Layer contain nine maps, so it's triple the size. 

The other chapters will be added to the branch later, letting you test all 18 of the expansion's maps. Before you dive in, you can check out the known issues here. Developer Crowbar Collective says things will get quieter on the update front, but only because the team the expansion ready for launch. 

Xen has grown over the years from a rework of the disappointing Half-Life level to a full campaign with lots of different environments and improvements. It was originally slated for a 2017 launch, but it's changed quite a bit from the original plans.

Valve might have shelved Gordon Freeman and his sci-fi misadventures, but Black Mesa developer Crowbar Collective still has one more job for the mute physicist. The studio's Half-Life remake was released in 2015, but since then it's been working on an additional and original campaign that greatly expands Gordon's trip off-world, and you'll be able to play it soon. 

In the original Half-Life, we don't get to see much of the alien world of Xen, but Crowbar Collective has been changing that. The Xen campaign doesn't just make the Xen level full-length—it's closer to a full game, or at least a meaty expansion. Check out the trailer from last year:

You'll have five chapters to work through, and the first two will be entering public beta on August 1. Soon after the beta release of Xen and Gonarch's Lair, Crowbar Collective will launch the rest of the chapters, Interloper, Nihilanth and Endgame. There are no dates for them, but expect them weeks, not months, after the first two. 

That's the last step before launch. Once all the bugs have been squashed, Black Mesa: Xen will leave beta. You'll get access if you have Black Mesa, which is currently on sale, and the betas will be available through the Steam Beta tab in the Properties menu. 

I'm increasingly less frustrated at the prospect of never being able to finish Half-Life officially. With developers working on fan projects to expand the original game and even bring Marc Laidlaw's vision for Half-Life 2: Episode 3 to life, there's still plenty of Half-Life left to play. 

Rise and shine! It's been a long, long wait for Black Mesa's final chapters. When Black Mesa (the modder-made recreation of the original Half-Life in the Source Engine) was released in 2015, it ended with Gordon Freeman's leap into the portal that takes him to Xen. The actual Xen levels themselves weren't yet complete. But today, at long last (we've been hearing the Xen levels were almost ready since 2017) , you can get a healthy taste of Xen as the team behind Black Mesa have made three chapters of the alien dimension available in a technical beta.

"The purpose of this beta is to collect bugs and feedback on a range of different computers," a post on the Black Mesa Steam page reads. "We have made significant improvements and changes to the Source engine, and we want the game to run as smoothly as possible. If you want to be on the bleeding edge of testing, opt into this beta. If you want the polished, complete Xen experience, you should wait. It won’t be long!"

There are some known issues with the Xen beta, such as drastically lower framerates while playing in 4K, issues with ragdolls in water, missing collisions with certain plants and roots in the swamp, and a few other little issues, so don't expect it to be a blemish-free experience. Players are encouraged to report bugs on the Steam forum or the game's Discord.

To take part in the beta, find Black Mesa in your Steam library (you'll need to own it, and if you don't it's currently on sale) and right-click on it. Select Properties from the drop-down menu, then choose the beta tab. Opt-in to the public beta and close the menu. You'll see Black Mesa updating to provide you with the Xen chapters. When you launch the game, you can select New Game and choose chapter 15 to start playing the Xen beta.