The story lines have been shortened, and important details have been left out.
Explanation:
As this is an opinion question I can only give my take on this but as I read reviews I've noticed people mention things that have been left out a lot, so most people are disappointed in movie version of their favorite books because important details are left out.
So she went to every beast on the land and fish of the sea and bird of the air and tree of the wood and plant of the field and made each promise not to hurt Baldur.