So the way it's going to be broken down is that the Devs will release an early prelude before they release the full game. This is because there's still a lot of work to be done in finalizing game systems, mechanics and tools while at the same time building a large open world with a lot of content. The Prelude is just a small scale version of the Full game and it'll go through the basic Alpha, Beta and then Final release stages. You can read up more on the prelude via the
official post by the devs.
People really want to play with what's already available (looking at the
public gameplay video will give you a rough idea of what to expect) so the devs are working really hard on getting a playable build available to Alpha tier backers as soon as possible. It's expected for there to be an early and very basic combat prototype that will be released some time next week (early March) and updated over time to lead into the Prelude.
Based on what's been mentioned, here's
my estimated release timeframe for the Alpha, Beta and Final release of both the Prelude and Full Game is as follows:
Prelude: (Prologue set a few years before the main game and lacking features full release will contain. The game demo/preview)
Alpha - March 2014 - Only available to Alpha tier backers
Beta - March~May2014 - Only available to Alpha and Beta tier backers
Final - Q2 ~ Q4 2014 - Available to all Backers
Full Game: (The full open world experience that will set the stage for future patches and updates. The main game)
Alpha - TBD (2014/2015) - Only available to Alpha tier backers
Beta - TBD (2014/2015) - Only available to Alpha and Beta tier backers
Final - TBD (2014/2015) - Available to all Backers
On top of that there's Insider forum access where the devs participate in various discussions about the game, and where they share some info (Text or Screenshots) about some aspects they're working on.
There's also the Development blog videos which are pretty great high quality videos where the Devs show and talk about recent features they've added to the game and development process.