how did gretel's room change

I'm not sure at what point in the novel you are referring to? Do you have a chapter in mind?

Its chapter 16 and 17, its actually pretty gay that the same guy responds to all the questions with the same response of what chapter are you referring to.. maybe if you read it you would be helpful, and dont respond to questions unless you know the answer...

the answer to how her room changed is she decorated it with nazi posters, and she got rid of all of her dolls because she is in love with lieutenant Kotler. point blank period.