No, it's meant to be confusing. It's more or less a preview of the end of the series. If you've watched Gurren-Lagann, remember the first five minutes of that? That's what the entire first episode of Shin Mazinger (and part of the second) is. Presumably it's expanded to episode length to show off how much of the mythos the series is drawing from for the sake of old fans, but more likely it's because Imagawa is not a very good storyteller.