Now that Shazam! is officially available for digital purchase, fans of the film can enjoy all of the adventures of Billy Batson from the comfort of their very own Rocks of Eternity. Exclusive as an extra to the iTunes version of the film is a director's commentary with David F. Sandberg, and he has some interesting insights to share.

First and foremost, it is clear that Sandberg was not used to working on movies this big. His previous works (Annabelle: Creation, Lights Out) were definitely smaller in scale, and this DCEU extravaganza allowed him to think bigger. It also gave him the opportunity to go back and reshoot some scenes that he thought could work a bit better if done differently. As he says, reshoots are a natural part of the filmmaking process, and they are "not always a bad thing."

The opening of the film ended up being reshot so that it could better set up the story of the film's villain, Dr. Sivana. A later scene where an older Sivana (Mark Strong) wipes out a boardroom full of corporate stooges (his father included, played by perennial DC sleazefather John Glover) was also rewritten and reshot — this was in the service of Sandberg setting up the monstrous "sins" properly, something that was necessary due to the huge part that they play in the finale.

Exactly what forms the sins would take was another thing that Sandberg had to figure out. He felt a certain freedom here, as the comics have depicted them in a number of different ways. He knew that he didn't want them to appear human, so they were turned into horror monsters. He was encouraged to tap into his horror roots here, and he did so — all the while being careful to make them only "as scary as Jurassic Park."

Sandberg also had to figure out how to personify "lust" properly — he didn't make it a representation of lust, he made it something that has lust for you, which is so much more disturbing. He also revelled in the Easter eggs added to so many of the film's sets — especially the Rock of Eternity. Some blink-and-you-miss-them objects are located here, things that Geoff Johns himself kept coming up with. Fans of the comics might recognize a fiery violin, as well as a spiked helmet. The ceilings on this set were purposely kept high, so that the VFX department could extend them in that direction. The surrounding walls were practical, which was important to establishing a sense of place.

Another tie to the comics comes when Shazam and his family are running through a different area of the Rock of Eternity, and they open a sequence of doors that lead to some wacky places. One of them contains three crocodile-beings sitting at a table, which Sandberg confirms are the "Crocodile Men" from the comics, hailing from the planet Punkus. Sandberg also mentions that he himself played all three of them in a motion capture suit, something that was suggested by producer Peter Safran.

Video of Shazam! - Exclusive Clip “Casting Zachary Levi”

It's no surprise that Zachary Levi (Shazam) and Jack Dylan Grazer (Freddy Freeman) have fantastic chemistry in the film — Sandberg mentions that he would often just let the camera run on the two of them to see what would come out. One of the scenes featuring this pair that got test audiences excited was the montage of Shazam's superpowers being tested, so Sandberg and the team went and added more bits to it. There ended up being far more moments shot than were actually used (the Aquaman joke was shot for this sequence, but became a post-credits tag instead), and during the commentary, Sandberg tells you how you can see even more of it.

He directs viewers on what to do at the beginning of the sequence — open the Shazam app on your phone (yes, the app that identifies songs and so forth) and let it listen to the scene. You'll gain access to a hidden featurette that goes behind the scenes of the montage, and shows a number of different tests that are not in the film. The "immortality test" is hilarious, but the "super smell test" takes the award for being the weirdest.

While details on the adaptation of the comics themselves (and the film's place in the larger DCEU) are slim, Sandberg does talk about the huge change to Billy Batson's origin. In the comics, Billy's parents are almost always dead. Here, his mother is alive, and... just didn't want to be his mother. It's a huge change, and it is one that had Sandberg wondering how long-term comic readers would/will feel. Geoff Johns, he notes, accepted the change.

When it comes to the larger DCEU, however, the moment that sticks out the most is the (kind of) appearance of Superman at the end of the film. Sandberg says that this was supposed to be a whole scene — Superman, played by Henry Cavill, was intended to come in, sit down, and talk with all of the kids.

Schedules can be a tricky thing, however, and Cavill ended up not being able to provide the cameo. Rather than change the button (which Sandberg loved), the team threw the Superman suit on Shazam's stunt double. They cut to credits before you see his face — while it would have been great to get some actual lines from Superman, the scene almost plays better as it is because it focuses on the reactions of the kids.

Does Sandberg mention Black Adam, still supposedly set to be played by Dwayne Johnson in some movie, at some point? He does not — Black Adam is not mentioned once. Neither is the Snyder Cut, for that matter.

Shazam! is available for digital purchase right now, with the commentary featured as an iTunes exclusive. It will say the word and morph into being available on Blu-ray starting July 16.