The story should be read back to front. Basically one of the so-called messiahs who came out of the heap of preachers in the first century became more popular than the others. He attracted the attention of the Jewish religious leaders and the Romans. They crucified him. It's what they did with difficult people, to put the fear of terrible death into the populace and keep them in line.
So now you have a whole group who were told their leader was bringing the Kingdom of God and now he was dead. What did they do? They put the Kingdom in heaven and said he was resurrected and would return to take them up to be with him. Then you create the ransom/redemption teaching so that it looks like the whole thing was planned. He had to die because of Adam and Eve's sin. This was all planned. The Romans just fulfilled prophecy when they killed him. It hasn't all gone wrong, everything is on track.
What are the holes in the story if taken at face value? If it was God who told Adam and Eve they would die for disobedience, why make imperfection hereditary so that everyone inherited old age and death? Why not make them die after they had children so that their kids were perfect? Or why not scrap that couple and start with another that could make a perfect race? Why make a law that forced him to kill his own son horribly when he could have said life for life doesn't apply here. This is a case of disobedience not murder. So many holes in this story it's like a Swiss cheese.