If you compare releasing a game to executing a military plot—and I honestly don't know why you would—Steam Early Access would be the bit where you're pushing miniature tanks across a crude map of the battlefield. There's a plan in place, and you sort-of know how it's all meant to shake down, but hundreds of things could happen between early development and final execution.
All of which is to say that the RTS sequel Blitzkrieg 3 is now out on Steam Early Access.
It's a bit of an odd prospect, this one, with a focus on asynchronous multiplayer battles. There will, eventually, be a single-player campaign. The current build contains one single-player mission, which, the developers say, "gives a good overview of how our single-player campaign will looks like". This version also contains "fully-functional" multiplayer with "certain restrictions in the progress".