As a narrative piece, the original Bioshock was great and really didn’t feel like the sort of game that needed a sequel. Commercially, its success sort of ensured that it would happen.
So despite seeming entirely unnecessary, and having a story that seemed very “appended” to the original world in order to fabricate a narrative reason for a sequel, this game was actually pretty damn good.
As a technical follow up, the graphics and the gameplay have all been improved. Okay, so the atmosphere and the story can’t compare to the original what with it being the second time around, but as a piece of interactive entertainment, it was a hell of a lot of fun.