Both the play and the book included this scene where Jonas' father kills the smaller twin. The choice to keep this scene was effective because it showed the frustration of Jonas when he realized the 'release', very well.
I know, I know. It hurts, little guy.
In the movie the Giver gives Jonas the memory of music to Jonas but in the book Jonas doesn't know anything about Music. It was effective because in the end Jonas knows for sure he reached elsewhere when he hears the music from the house.
Listen, Listen to what is calling you Inside.
Both the book and the play included this scene where Jonas gets emotional when he sees Asher and Fiona playing 'War'. This was effective because it shows how big memories can affect Jonas.
What's wrong Jonas? It's just a game. You ruined it.