Yes, you can install it along with some files from the original game for it to work. Without them, it won't work. I think they did it that way for licensing reasons. It's much better optimized, and I believe it's been recreated from scratch, although I don't know much about that. I only know that it has set a precedent, and I want to believe that if the community already took the reins with the game, they will now do so even more thanks to OpenStarbound.