"I'm not a really big fan of expanding things just by linearly adding to the experience, adding a new campaign, as much as I am of enhancing the original experience and adding replayability to that experience," he told 1UP. He goes on to mention that plenty of plasmids were cut from the game. (Hint, Hint.) The way we see it, anything that gives us a reason to play BioShock again is a good thing, we just hope we're past the glut of holiday gaming goodness when it happens.
