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 (opens in new tab). "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 (opens in new tab) or the game's Discord (opens in new tab).
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 (opens in new tab)) 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.