When Shazam attempts to fly in the mall during his battle with Dr. Sivana, a group of seemingly unimpressed shoppers can be seen in the background paying him little mind. Those were actually visible crew members that were filmed by accident. Shopping bags were inserted digitally to give them the appearance of shoppers and cover the mistake up.
In the original comics, the 7 evil statues on Shazam's Rock of Eternity were originally known as the Seven Deadly Enemies of Man, a more family friendly version of the same idea. Sloth was called laziness, wrath was called hatred, gluttony was selfishness, and lust was injustice.
At the abandoned factory where Freddy trains Billy and records his powers, the sign "Ace Chemicals" can be seen in the background. That's the factory where the Joker was born. (Batman (1989) renamed the factory Axis Chemicals.)
In the comics, Captain Marvel had a magical talking tiger, Mr Tawky Tawny, as an ally. In tribute, throughout the film Billy Batson displays a liking for tigers:
- he likes stuffed tigers (he actually hands one to a scared little girl)
- his backpack has a tiger on it.
- as Shazam his cape clasps have tigers on them.
- when Shazam! is performing "lightning from my hands", the background music being played is Survivor's "Eye of the Tiger".
- In the flashback with Billy and the theme park with his mother, she wins him a compass with him exclaiming that he wanted the plush tiger prize instead.
Originally, this was going to be one film with Shazam and Black Adam meeting and clashing, but the producers decided to split the film into two origin films for both characters with Black Adam (2022) being its own story set in Ancient Egypt with other heroes. However, Black Adam is mentioned in the film as an ancient champion the Wizard had chosen who went bad. Dwayne Johnson, who produces the film and who was cast as Black Adam, had his facial features used for the magical portrayal of the champion.