Also, like the first movie, it's fairly well written, well acted, has really good special effects, and generally a fun time at the movies.
Shazam 2 picks up at least two years (maybe 3-4 years, since Billy is about to turn 18 in this movie but one character specifically says 2 years at one point). The Shazam family have gotten a bit of a reputation as some what incompetent super heroes despite trying their best to be a great hero team.
Unfortunately, Billy, breaking the wizard's staff at the end of the first movie, allowed two of the daughters of the Titan Atlas to cross into the human realm, and they want to reclaim what has been taken from them.
Shazam 2 totally works as a standalone movie or as part of a two movie arc. While it does reference other superhero characters you really don't need to see anything else to enjoy this film.
If you know Black Adam is actually a part of the Shazam comic book series, and you skipped seeing that film with Dwayne Johnson in the title role, it doesn't matter at all. The only reference to that movie is a name drop of The Justice Society. Beyond that you could act as if Black Adam never happened (and, as far as everyone in this movie goes, it didn't happen or they never heard anything about it).
To me, that's the biggest problem the film has. It doesn't pay off who that extra seat is for (from the previous film... presumably Black Adam?). Not only that. They never even mention it. Reportedly Dwayne Johnson turned down a chance to cameo in this film so I imagine there was little point in teasing the return of the character for the moment.
While the Daughters of Atlas, played by Helen Mirren and Lucy Liu, are actually quite engaging with both actors delivering suitably threatening performances, they do seem a little like the 'B team' in terms of being the movie's villains. Even though their back story is well within the context of Shazam lore and their presence ties back to the first film.
It makes me wonder how much better this film could have been if Dwayne Johnson hadn't been so ham fisted in pushing his character to the forefront of the entire DCEU. There was definitely room here for Black Adam to have initially teamed with the heroes but then turn on them at the end, setting up a third film hook that people might have been excited to see.
That aside, this is a much better film than Black Adam. It's better constructed in terms of story. It's humor is done better (and not grossly mistimed, or uncharacteristic, like that movie). Even though not all the characters are as utilized as they could be, all of them seem like unique individuals, and at least get to contribute to the story in a way that makes sense with who they are.
I genuinely like Zachary Levi in the role of Shazam. The only problem here is Billy Batson isn't really a kid anymore. While Zachary is great, it is starting to feel a little like he's still playing 14 year old Billy rather than 17 year old Billy. If they get a third film (not looking too promising at the time I'm writing this), Zachary may need to work on aging up his call backs to how Billy would think.
It is entirely possible for this Shazam heroes team to carry forward into the new James Gunn DCU since their hero forms are magically created. They could take the opportunity to recast the child actors, and cast older for young (like Hollywood used to do all the time) so they don't age out quite so fast, and they could recast Black Adam entirely.
That way Zachery could keep going with channeling a younger Billy, and it wouldn't seem quite so weird that an almost grown man, is turning into an even older grown man.
Overall, while I don't have a lot to say about Shazam 2 in terms of the movie itself. I can say I had fun watching it. It doesn't deserve to bomb at the box office because it is a well made, solid movie that, unfortunately got released during a transitionary period, after a related film failed to impress because it was actually not as good as it should have been.
As a hold over from the DCEU and the Snyderverse, Shazam is still the brightest light in terms of guaranteed entertainment... even if it isn't the most memorable.