@Zetskey I downloaded the game yesterday, really eager to play it as I follow it almost since the begginning, and saw that the test was over. I didn't know about the lag and else, but I didn't start to think bad of them. I've read the article explaining the problem that happen, and I understand they had to close it. They really didn't expect a problem like that, and it might be a problem coming from SpatialOS, so how do you think they could handle it ? And as other people said, it's a stress test, it failed because of this bug, but at least they found it, and now they can try to fix it, or wait for the SpatialOS guy to resolve this problem.
We just have to be patient, I think I can say that I know how Dynamight work, and I can tell you that they're trying all they can to solve it. I suppose you got the popup saying that you have to buy Alpha 2 pack because we're currently in Alpha 2, but it doesn't mean that people can access the game in them meantime, because servers arent' up.
Edit : I saw that it seem that yes, the servers are up for the Alpha 2 backers, but I suppose they let them play because it will not occur any problem.