It's amazing, continues where BVS left off, and shows subliminally why batman killed and now his killing somewhat makes sense. Seeing as he return to killing if the nightmare occurs, but on a larger scale. Spoiler alert: batman kills because he is both this world's batman version and the flashpoint batman which is notorious for killing. Bruce loses faith in all he believed in and falls for his dark desires which rage in even the comicbook version, but this batman has no one to help him through it, which ceases with the befriending of diana and superman. Then batman is full of hope and faith again, he just hopes for the best even when the odds are stacked against him and at a pivotal point in the story flash breaks the light barrier (runs faster than light) to save his teammates and then the flashpoint occurs, either flash helps his teammates and the world is turned into the one we see, or he fails and decides to do something else like taking them away to regroup and fight back another day (my own conclusion) creating the startup for the nightmare.