Do NOT avoid spoilers for this movie. It will save you time and money.
This movie is essentially four short stories in one film, yes they all connect, but it's still four different stories.
Plus, once the plot is FINALLY explained the story just gets worse and worse; but that is the only thing that is explained, the "What" of the plot. Any questions of "Why" or "How" are left unanswered.
Also the cliffhanger at the end is completely random. What happens is that when Martin Manhunter (not the one already established, a different one) is in the process of self-destructing War World (for reasons the film only mentions and doesn't go into) a portal opens up and some purple chick with fire hair flies out. Miss Purple says that Wonder Woman, Batman, and Superman are needed, then teleports WW, Bats, Supes, and herself back through the portal onto some spaceship. War World blows up assumally killing Martin Manhunter (again, not the one already established), Mongul (who does a poor job of being the antagonist), and Lobo (who A: doesn't do anything (not really, be real about it), B: doesn't have a purpose in this film, and C: he's not really gonna die because he's Lobo). Anyway back on Miss Purple's spaceship, she tells the big three that everything and everywhere is in trouble, so that tells me the next film will be a crisis story, which means DC might be rebooting their animated universe again.
Save your money, don't watch this movie, watch a summary on YouTube (if someone decides to make one).