Right now they have released one version of the game (plus some minor patches). They considered it "pre-alpha". It is a couple months old. On my system it is quite stable and runs smooth.
The next founder release is supposed to come out either late this week or next week (they said no earlier than August 13th). Their timeline had them moving to Early Access in late summer, which it is. Once they release Early Access, you will not be able to become a founder or an elite founder.
In the current alpha:
Graphics: Pretty good, I think it will get better. The unit models are capable of very high detail, but the current pre-alpha much of that detail is turned off. There are not many effects, and I expect that will also be improved.
Gameplay: it gives you a general idea of how the game will function, essentially like most other infinite resources base-building RTSs out there, with some features pulled from a variety of sub genres. It's mostly build units, conqueror territory, research some stuff, and kill the enemy with your vast army. The current alpha does not have much depth beyond that.
AI: You can play against one AI opponent, who was not very smart but I think has been improved a little over the last couple months. I know the AI has significantly improved in their internal build which we will be getting to play soon.
Multiplayer: If you both have the game, you can play against a friend. I have not tried it, but I think it works.
What little we know about the August update is based upon some forums posts in the Founder's forum. We should see the DX12 version, the stronger AI, larger maps, some UI improvements, some battle group management improvements, and some logistics improvements. I strongly suspect there is much more, but we don't know yet. They'll be giving elite founders a steam key to give to one of their friends to play multiplayer. Unfortunately I don't think I can give any real specifics. I can say once the next patch comes out, they might go early access soon after, so you'll have a short window to decide if you want to become an elite founder, which will give you a huge discount in the long run on all future DLC and expansions.
