This movie absolutely murdered the book.
I loved the book The Host ( I have read it many times and know parts off by heart) and this movie almost ruined the book for me. I did keep in mind, and you should too, that this is a movie adaption of a book so it is bound to be lacking somewhere and in my opinion movies are never as detailed or in depth as the book but this movie was almost unacceptable.
The director and screen writer missed IMPORTANT scenes and events such as Wanda's face getting half grazed off on the rock wall, they did a terrible job of covering her and Kyle's fight (when he tried to kill her), then there was no tribunal or soccer match to lift tension. There was no Wanda helping Walter as he was dying. There wasn't even a Walter in the movie. Also they missed the best quote/part in the book; when Ian says to Wanda something along the lines of "It's not the face but the expressions on it, It's not the voice but the words you say with it" There was nothing of that sort. Also the only characters actually named in the movie were: Wanda, Mel, Jared, Ian, Jaimie Kyle, Jeb, Maggie and 'The Seeker' or Lacey (who managed to wake up and remember her name straight away). Lily, Aaron, Brandt, Wes, Walter and all the other humans in the resistance weren't mentioned.
So all in all, this is an amazing book and the film did not do Stephanie Meyer's work justice.