I am not sure what I can add to help you decide whether or not this game is something you want. But I will say that I think people should wait to play 999 and/or Virtues Last Reward first, as this brings up many points from other games. That said, yes you can play this without the others, you might just be a bit confused. Also, keep a piece of paper or small notepad handy for puzzles/codes/etc.

I was not a total fan of the cinematics, but I found myself taking penty of screenshots, especially of Gab the dog! There wasn't much else that I disliked either.

I liked the puzzles, the updated flow charts, and the ability to play the story as different people, and the characters themselves. I don't want to spoil anything, but some of them are pretty interesting and way more then they seem.

Therefore, the short version is that I fully reccommend it with no reservations.