The Early Access means that you can play CivCraft months before it's publish.
As we will develop new features, we will post new updates to the early access and allow you to play with the latest features.
This also means that you will receive the final (published) version of CivCraft for no extra charge.
You will be entitled to all of our CivCraft versions, including the early access, without installing Steam. We will send constant updates and versions for you to enjoy, as well as the DLC's (for the DLC tier).