Shazam is one of the oldest of DC's stable of comic book heroes. He was originally a knock-off of Superman created by Fawcett comics, and DC's lawsuit made Fawcett cease publication - eventually DC got control of the character.
The story starts in the 1970s with Thaddeus Sivana being tested by the wizard Shazam (Djimon Hounsou) to see if he's worthy of the powers Shazam can give him. He's not, and Shazam casts him out. We jump forward to the present day to find Thaddeus (now played by Mark Strong) hasn't forgotten about the wizard or the power he represents. We also meet the 14- or 15-year-old Billy Batson (Asher Angel) as he's being moved into his Nth foster home (he's run away a lot, looking for the mother he lost when he was very young). Soon after, Billy ends up in the same cave where Thaddeus was rejected, and is imbued with the powers Thaddeus was considered unworthy of, becoming the hero Shazam (Zachary Levi). Hounsou gives a long recitation of the new hero's powers: most obvious is "the strength of Hercules," but one we'll get back to is "the wisdom of Solomon." Then follows a fairly long section of the movie in which an adult-looking superhero acts like a ten year old child (not a 14 year old) as he and his foster brother discover his abilities. But eventually he has to do some growing up as the evil Dr. Sivana comes into his power.
The movie is officially set in Philadelphia, but pretty much everything to do with public transit (including exterior shots around stations) were shot in Toronto (Lower Bay Station has appeared in 50+ movies over the years, including this one). I had fun playing name-that-place.
I watched a movie some years ago that explained that when you're dealing with both younger and older versions of a person, you get the older one to learn the ticks of the younger one so they act alike. The reverse doesn't generally work because five year olds or twelve year olds aren't usually good actors. One of the things that bothered me the most about this movie was that Billy Batson was quiet, and Shazam (the superhero, not the wizard) wouldn't shut up. Asher Angel and Zachary Levi are good choices as the teen and the magically enlarged teen/superhero respectively as they're similar in appearance and movement ... but they should have made Billy talk more and Shazam less so their behaviour would meet in the middle. Obviously this is more a failing of the script than the actors. The other thing that really bothered me was all of the silliness as Shazam is learning his powers. I get he's just a kid ... but in the original comics he had access to "the wisdom of Solomon." Trust me, he ain't using that in this movie.
Overall it was fun and amusing, but its lack of depth means I'm unlikely to ever revisit it. For comparison, I've already re-watched the equally nutty "Spider-Man: Into the Spider-verse" twice because it's so well and thoughtfully constructed.