Ken Ishikawa proved that the world of Go Nagai and its characters, any writer can write stories based on this world, which he can create independent and sequential stories like those in Marvel and DC comics. Unfortunately, this manga was short, consisting of only ten chapters. However, its content satisfied me with the assembling of the characters and making them interact with each other and not putting them in a crossover story just for the sake of the crossover. There were ideas from which he could make a long epic story like with 50 chapters at least. So with ten chapters, everything happened quickly and rushed without explanation,but in general I was satisfied.
Grendizer which is my least favourite Go Nagai super robot story, I loved him in this story with him coming to save the rest of the team was amazing.

Ishikawa also gave this team of heroes the name (Iron Dynamic Team) who eventually all merged into one robot and formed into a giant robot called Hyper Dynamic Saga.
And of course, since Ishikawa was the one who worked on this story, he made Ryoma the one who leads the heroes.

Overall, if you read or watched the following stories of Mazinger Z, Great Mazinger, Steel Jeeg and Getter robo saga, you will be entertained with this short crossover story.