"For you to talk about how it's OK to be vulnerable, you have to be vulnerable," Gunn told the "Superman" star

This story discusses plot developments in “Superman,” which is now available to purchase on digital VOD. James Gunn provided a rare and fascinating look inside the process of making “Superman” on Friday,

Edited together as part of a 60-minute making-of feature, the seven-minute video shows Gunn walking Corenswet through Superman’s big final confrontation with Nicholas Hoult’s Lex Luthor, and specifically the moment when the Man Of Steel reminds Luthor he’s just as human as the rest of us.