Barry was able to persuade Thomas Wayne to help him by telling him about Bruce still being alive in the main timeline, and the two of them later recruited Cyborg, Element Woman, Shazam and others to help.
Bruce Wayne was killed in Crime Alley that fateful night, leading Thomas Wayne to become Batman and Martha Wayne to become The Joker.
Wonder Woman and Aquaman were at war with one another, and their conflict saw the destruction of Themyscira and London.
There were a number of shocking changes as a result of Flashpoint.