Personally, the only changes I would really make would be A) to let you skip conversations, and B) to add more challenging puzzles. I often play the games over and over again and don't feel the need to sit through them blabbing when I've already beaten the game several times.     And I loved the puzzles in the first two games but felt the third game wasn't very challenging.  Don't get me wrong, I love the games, I'm just hoping for more difficult puzzles in the fourth game