I just powered through all 10 episodes, there's an awful lot to like here.
There are hints at a larger D.C. Universe, Eel O'Brien shows up as a newspaper photographer, that's the character who would become Plastic Man in the comics.
Jim Corrigan shows up in his pre-death Detective format, before becoming the Spectre.
We don't get a John Constantine or Zatanna/Zatara, but Papa Midnite is present and accounted for.
The Green Arrow villain Onomatopoeia pops up in one episode, which was fun to see.
At one point, there are orphans introduced in Robin order... Dickie, Jason, Stephanie and Carrie.