Spoiler Alert!!
Thomas Wayne's the batman in this movie and became more bad-ass than Bruce. He unmercifully kills any villain in his way rather than sparing them like the way his son Bruce does.
Maybe that would be enough to reveal what's on the movie :D
Overall, the movie is so brutal that for me I wouldn't recommend for little kids to watch.
It's an action-packed movie of an alternate universe of the Justice League to correct the past, to bring back reality and battle to stop the fall of the human raise.