You can talk about it. You will probably be allowed to post pictures and video too, but Uber is reserving the right to ask you to take down pictures and video. BUT, keep in mind that the alpha is for bug testing; there will be horrible, horrible, bugs. There will be times where the game is not fun. Don't go dumping a pile of steaming hate on the game when it crashes, or when one unit dominates the gameplay.
There is no NDA. If you livestream or take video, however, PLEASE clearly mark it as alpha footage. We'd really appreciate it.
Have you guys considered adding such a notice to the game it's self? Just have a bit of text saying something like "Alpha build, not indicative of final game" rendered somewhere out of the way. That would ensure that the message is anywhere people are showing the game and I'm sure most of us wouldn't mind it too much.
There already is (top corner says "prealpha" right now, though I guess alpha has already started). Problem is to make it big enough to be readable in most streams means making it obnoxiously large for the person playing.
