"Godzilla's Revenge" is a children's movie, no doubt about that. There's no "revenge" to it. The story revolves around a child in shorts (thankfully not named Kenny) who endures torment and abuse from his schoolmates. Since the idea of going postal hadn't been invented yet, Ichiro spends his afterschool hours dreaming of Monster Island and Godzilla's son Minya. Running on the same track in the direction of this plot are two bank robbers.
Much like "Casino Royale" was James Bond without Sean Connery, "Revenge" is Godzilla, sort of. One might look at it as a satire or spoof. It shows Godzilla; he fights and yells, but he isn't laying waste to anyplace in Japan, and *shudder* he's a dad. This is not the Godzilla I grew to love. That having been said, Godzilla does impart wisdom to his son Minya, and by extension to our movie's child.
The idea of fighting one's own battles is important, as well as having the courage to stand up for yourself and your convictions. The lessons taught by Godzilla (I can't believe I'm writing this) are ones needed by children, regardless of their circumstances. It's done in a way that is subtle and fun, yet effective.
On the adult level, however, I'm afraid that you're simply going to have to turn your brain off for this one. I could've sworn one of the bank robbers was Joe Pesci -- but I could be wrong. They are simply too buffoonish to be believed, but it is necessary to make them this way so that the ending can play out as it does. However, there is enough in them to make them more than two-dimensional (i.e., the one robber's drinking problem). It's "Home Alone" without Macauley Caulkin -- and that's a good thing.
Sterno says show "Godzilla's Revenge" to the children in your life.