HIGHLY recommended that you start a new game. Your game WILL encounter errors if you load an old save.
Here's just some of what has been changed:
95% of ALL the old art has been replaced.
98 % of all CGs have been replaced
Lots of new scenes, new content, new characters, new visuals have been added to old scenes, even some storylines have been changed slightly.
Player can now free roam more
You can interact with characters in a much better way
Added a "New Game Plus" option that skips the early grinding
Removed all the silly potions, puzzles and the grinding
Removed the need to Sleep all the time.