I spoke with Manticore Games recently. They visited Handmade Seattle, and showed an interest in inviting some of the game-specific project creators to their private CORE Alpha. Just recently, I managed to have that invitation extended to the Handmade community.
If you're interested, here's the sign-up form tailored for us. Note that I don't get paid or sponsored. My conference is independent, so this is an optional networking type of thing.
See you around,
P.S. Their demo is impressive, but I had to sign an NDA so as to not divulge how it works. That may or may not be the requirement for the alpha as well. Thankfully the agreement is straightforward to read, but if you're asked to sign it and don't want to, simply decline and wait for the public release.