Yep. Playing it right now. Adds an entire new map to the game, Solstheim. It's about the size of the Reach in Skyrim. Lots of new and unique barrows, caves, mines and Dwemer ruins, and some really difficult puzzles inside of them. Adds a few new types of armor and weapons. New enemies of course since it's an entirely new region. Some new shouts too, which are pretty bad ass. Doing the main quest alone, it adds about 6 hours or so of gameplay. There are a lot of side quests too. Pays a lot of homage to Elder Scrolls III since one of it's expansions took place in Solstheim. This version looks completely different though since the Red Mountain eruption covered the place with ash and destroyed a lot of the trees.
The boss is pretty tricky to defeat so watch out.
