To be honest, the play was... okay. Just okay. The dramatic structure set the show up as a conversation between father (Siegel) and son (Superman himself), and there was a lot going on there. Unfortunately, the play just recycled conventional ideas about the creation of Superman, and it really didn't have anything new or noteworthy to say. There were also "imagination sequences" in which Siegel was thinking of the Jews in Nazi concentration camps whom Superman was powerless to save. I know, that seems like strange sentence, and the play really wanted to make all these connections work. But they never quite did. Maybe it was because I wasn't seeing the full mounting of the show (the script kept talking about the comic book panels coming to life, and it was heavy on projected images), but the play never quite achieved its lofty aims.
It was funny, well-written, and entertaining, but it wanted to be so much more. And ultimately, it was about a guy in spandex tights and a cape. I'm all about finding deeper meaning in comic books, and using the medium of words and pictures to capture something meaningful and important about humanity... but you can never forget that it still just a story about a guy in a cape.