So PC is listed but isn't this just a collection of what they already have on Steam? I wonder if this just means they're going to add a bundle to Steam and GOG whereas previously it was all just available piecemeal and only on Steam?
At a guess, it's going to be as is but updated with the new features (rewind, mirror mode [whatever that is], online play). Hopefully some optimisation too, I remember having hitches with it and I've heard of others having similar problems. I can't really see the sales model changing.
EDIT: Oh I forgot about the achievements, aye maybe it will be a single release.