As I started watching Superman/Shazam: The Return of Black Adam, I was first and foremost surprised that it's only 23 minutes long. As I came looked it up, it turns out that this dvd release contains this new animated feature and the three previously released bonus features of The Spectre, Jonah Hex and Green Arrow which were available on the two-disc versions of the last three DC Direct animated releases. As much as it makes sense to me, it certainly feels like a rip-off to buy this dvd. Which I did not.
But back to the main "movie". I actually really liked it. It was mostly a Captain Marvel story and his origin with Billy Batson, but ya pretty much have to throw in Superman to make people notice. The animation was awesome with some really cool fighting and the story pretty to the point for the time allotted.
I haven't been a fan of the Superman duo releases DC has done, but I really liked this one. I say you should give it a shot and watch it.