I think that Dorgon 5000 just meant that:
1. He hopes that TSoG will be a really long game and
2. He hopes that the downloadable demo will be finished soon.
But, just in case, I'll try to clear things out:
- Currently there is an online playable demo (a beta version);
- Soon (though I have no idea how soon) the online demo will stop being updated and a downloadable (and, I think, more complete) demo will be available;
- The demos will contain only a part of the full game (and may be used as a marketing tool);
- The full game will be sold;
- For now, there isn't a release date for the full game.