Its a series of four shorts.
The Superman/Shazam short was okay but a bit of a letdown because its another one of those epsiodes that shows Superman as much weaker than he is. The episode felt exactly like the Sinestro episode on Superman:The Animated Series where Superman was basically just there to try to hold back Sinestro until Kyle Rayner could become Green Lantern. Replace Sinestro with Black Adam and Green Lantern with Captain Marvel and its almost the same.
The Spectre was kinda crap.
Green Arrow and Jonah Hex is where it really shines. I really loved the Jonah hex especially the ending.