Last year, Black Mesa was one of the first Steam games to be Greenlit by you, our amazing fans. We've had quite a year since then, with a lot happening internally that we haven't been able to talk about... until now. Black Mesa has been given the opportunity to be sold as a retail product on Steam! This is an incredible honor - one we never expected - but also one we found hard to accept.
You can read the full thread here.
Also, I'd like to shed light on an interesting post written by their Lead Developer your-name-here:
The free version of the game has been ported to Source 2013. Right now, that version is functionally equivalent to the released version of Black Mesa we released a year ago. When we got on greenlight, we were forced to move to another engine. Right now, we can't tell you what that engine is due to our licensing agreement. Being on this new engine allows us to change how the engine works, modify tools, etc; things we plain and simply cannot do for the free version. I plan to open source the black mesa code for the free version.
What could it mean? Dare I say, Source 2? That's enough fueling the hype machine for me today, I'll let you all interpret that however you like.