Well if I quote their website (
http://www.divinitydragoncommander.com/blog.php?news=41):
The Imperial Edition is a special collector’s edition of Divinity: Dragon Commander and is free for everyone who preorder(ed) the game(*)
The Imperial Edition is a special collector’s edition of Divinity: Dragon Commander and includes:A unique development documentary video
An extra campaign map that has dragons fight for control of the Earth
A golden skin for your Dragon Emperor
A beautifully remastered version of the soundtrack by Kirill Pokrovsky
Dragon Commander’s best kept secret: an overview of all the choices and consequences in the game (you’ll be amazed)
Immediate beta access(**)
The Imperial Edition will be made available on the day of release as downloadable content, and people who preorder will receive a download key. Anybody who pre-purchases will also receive a Steam key that will unlock beta access.
The Imperial Edition will remain available after release, but will then be sold as a separate DLC.
