A couple of afterthoughts I wanted to add. I mention the bio-pic genre in the review. Having seen scores of them I think I’m fairly expert on the topic (see my monster three part blogpost series which begins here). It seemed too much of a digression to include in the review, but some examples of musical bio-pics that work better as art by focusing on an aspect of the story (rather trying to tell every goddamn thing) include Walk the Line (2005), which concentrates on Johnny Cash’s efforts to win the heart of June Carter by kicking drugs; and (more to the purpose) Gypsy (1959 stage; 1962 movie), which focuses on Gypsy Rose Lee’s problematic relationship with her domineering stage mother.
That said, one important aspect of Cagney’s life that got short shrift in this musical (another tangent) was his relationship with the most important person in his life, his wife and former stage partner Willie. I can’t imagine telling Cagney’s story WITHOUT making it about that relationship. It was the most important one in his life personally, professionally and even politically, and she was there with him as his primary confidante and adviser from the Alpha to the Omega. But in this musical, she is introduced and then forgotten, becoming no more than (as the Mad Marchioness and I like to joke about June Lockhart on Lost in Space) “The Woman Who Performs the Important Function of Bringing the Sandwiches”.