Zelda's AI and Physics engine is what makes this game come alive, but it may also be the reason for some performance issues
Good graphics are good to have but to really make the game special you have to have a powerful AI and Physics engine to go with it, Zelda has really kicked something off here
Here is a comparison between Zelda and a more traditional game
Part 1 - https://www.youtube.com/watch?v=aVPXKdSEGNQ
Part 2 - https://www.youtube.com/watch?v=qEGWtyJAkO0