(Stream is now over)
Okay, here's what we know:
Game is called Cyberpunk: 2077.
It is set in Night City, and is based on the classic pen-and-paper RPG Cyberpunk.
It's fully open world, unlike The Witcher 2, and comes with lots and lots of customisations - such as implants, weapons, and so on.
The style of the game is very much like Blade Runner, the indoor areas of the Citadel in Mass Effect (only grittier, I guess), and so on.
It is futuristic and heavily based on technology, but is also decadent, chaotic, and revolves around some struggle with a totalitarian, corporate system, I believe.
Personally, I can't wait for this!