Please see the Pre-Order Links pinned topic for the latest news on prices and ordering.
The game is vaguely complete but not yet completely polished, and there is no demo yet available. You can buy in now for a small discount, but at THIS point you may prefer to wait for the full release which is coming soon.
When you order, you'll get a download/installer for your OS like you would normally, as well as a license key. When you run it, go to the options menu and you'll find an Updater. Click on that, and you can check for updates and download all new patches. You will need your license key to download patches.
As you play the game, if you run into errors, you should end up on a traceback screen with several buttons. If you click 'upload traceback' then as long as you're connected to the internet, it will send us the error report so we can investigate it (and also offer you a patch, in case we've already fixed it!) You will also have the option of rolling back - backing up to before the error happened, so that you can possibly make a different choice and keep playing.
Beyond bugs, feel free to make comments about anything you'd like to see. I don't promise to act on all requests, but it doesn't hurt to ask.

I can't answer questions about plot/characters/setting because many things will be explained later in the game or series. You can speculate to each other if you want, just don't expect me to tell you. If you're not sure how something works gameplay wise, though, ask away!
Okay, here we go.
Windows Preorder
Macintosh Preorder
Linux Preorder