Drawn by the trailer, I approached this movie expecting perhaps too much. It was not very humorous and neither was it particularly novel. The concept is fine but the execution (no spoiler intended) didn't quite succeed. I see that Waititi has been nominated for awards for adapting the screenplay. I am now reading the book, "Caging Skies" and there is some similarity with the film but many differences. The focus is on different characters. The book is far from being a comedy. In "Caging Skies", Adolf Hitler does not appear as an imaginary friend. Johannes is much older, 14 - 20. The film uses only the first half of the book. There are many scenes that are not in the book. The characters are stereotypical, as in the TV series "Hogan's Heroes" but the leads, especially Jo Jo and Scarlet Johannsen, are excellent. This is a quirky movie and quite enjoyable but less than it might have been.