I have just completed this and all I can say is is amazing.
The first half of the game is a bit slow and (re)introduces the story and game play mechanics. Once the game takes a notable turn at about half way it really picks up and continues to steadily improve in story line and challenges.
It stays true to the first game with a highly emotional narrative. The player becomes deeply invested in some of the characters. As the story goes forward some of the choices the characters make and situations they are placed in put this attachment to the limits and push boundaries like no other game.
All this accompanied by a beautiful rich world with highly detailed and thought out environments. 9/10 will play again and recommend