The way I understood, they're not using full game for promotional purposes yet. You know, when you have developed something truly great, and don't want the public to see everything to soon, etc. I have done that myself once
. If you have something amazing, you want to hide it (for some reason)
And I think this line in
this thread should confirm my thoughts:
*In the gameplay videos we've seen the presenter briefly open up the game's world map on several occasions. The staff on the community site is assuring that we did NOT see the full map. The full map (whether in screenshots or a new trailer) will be revealed in the next two weeks.