First off, is the game out and playable?
Not yet, we are currently in Pre-Alpha stages and only the devs and their family and friends are currently able to play and theyre only playing VoxElyria.
What is an approximation for the release?
The approximate for release is Late 2019
Will these "pledge your support" things effect actual game play?
I think the pledge your support you're referring to is the pledge packages via the store.
They affect the game play in the sense that each package depending on how high you pledge create the history and start at different levels of the kingdom via these pledges that can be bought.
However, Elyria has many different paths you can take to creating your own story that "being king" isn't one of the only stories you can choose to go. If you do wish to go that path you can work your way up from the bottom to the top to acquire that role; Or you can be an amazing well known blacksmith, or even an adventurer. Where your path takes you is your own.
They are considered "fundraising" at the moment as the game right now is entirely crowdfunded by us to help the development.
As Johan stated above, currently the earliest game play you can experience is VoxElyria in approximately April, there isn't a set date for it yet.
The way the releasing works though is at the start of VoxElyria it'll only be available to Alpha 1 backers, so you would have to have a pledge that has Alpha 1, or bought alpha 1 along with your Elyrian pledge to get access at first.
Through the process of them adding more into VoxElyria and having more content to test it'll be released slowly through the various stages: Alpha 1, then Alpha 2, then Beta 1, then Beta 2, then eventually to everyone with Elyrian pledge and higher.