Release is when it's done and when they feel it's ready. The game has changed A LOT since it's started closed beta. Quite a lot of changes they made that didn't really fix and they're reverted...they're still trying to figure things out.
And yes, you can play w/o an invite, go download. It's not in closed beta anymore, it's in open beta and there's still a fair amount of changes being made. --- Solid's snake still shoots liquid, it's just that it's null.