Per the source, it did a deeper dive into the trauma that led the billionaire to become the Dark Knight (presumably it would have done more to utilize Nicole Kidman’s psychologist character, Dr. Chase Meridian), and the production shot “a sequence of Wayne facing down a giant, human-sized bat.”
Whether or not that is a fantasy sequence or not is not made clear (could it also have been the movie’s attempt at including Man-Bat?)
Obviously that’s not enough material to fill the 40-minute time difference between this early version and the familiar one, but the new report adds that there is also an entire Bruce Wayne subplot that got excised.