The Unfinished Swan's developers, Giant Sparrow, left some surprisingly finished bits out of the original game. There was the ability to build rivers of ink and a whole library of unfinished books.
The Unfinished Swan was a very unique game that captured the imaginations of all who played it. Tossing around balls of ink to discover that black and white world evoked a sense of discovery that very few games can aspire to. That being said, a number of features were left on the cutting room floor before the game ever met its release date.
There was a mechanic where you could build rivers of ink 10 feet deep. There was also going to be a whole library of unfinished books where you could see the first chapters. Ian Dallas told Joystiq, "it seemed cool. We had a whole playable prototype, it worked, it was there, but it wasn't fun." So those two mechanics got the big old axe.
Playing what if with The Unfinished Swan is fun, but we're very glad that the game made it out with what it did have, a lot of unique gameplay, mystery, and charm.
There are rumors of other ports, but Ian Dallas couldn't confirm these or say very much about Giant Sparrow's new game, Edith Finch. He did mention in the interview that they may have a developer for the new game, and considering the heaps of praise they've given Sony, it would be reasonable to assume that Edith Finch may be another Sony title.