I played about an hour today and its ok. The death star ground maps are pretty decent, although I think bespin is better. The maps capture the tight corridors and constricted feel of the death star, even stuff like the gravity gen rooms, but a new mode of the game is that death star space mode (which isn't really new) and its a 3 part game: first rebels try to take down a star destroyer with x and y wings, if that succeeds then they have to escort r2d2 from the detention cell block to an escape ship, and if that works then the rebels have to do a trench run on the surface of the death star ala Luke's "womp rats" moment. The last part is pretty fun, the space combat of part 1 is kinda bad though since its really, really, really basic with no frills - backgrounds look pretty but are really static, you can't destroy asteroids or ship floating junk, etc.
wouldn't really recommend the new DLC as something to buy, but if you already own the deluxe/etc its fun to play for an hour or two, then you are kinda bored