A man is shot in the throat while speaking mid-sentence and some mild blood is shown pooling around his neck. This is sudden and very upsetting but not graphic.
The dead body of a man is seen after he was shot to death, there is a decent amount of blood shown on another man's hands and the dead man's body and neck.
A dead woman is implied to have been placed in an elevator, her blurred out body is shown and some blood is seen splattered on the floor.
Several scenes of dead victims of gunshot wounds, no gore is shown and blood is very minimal.
What really pushes the R rating is the beatings and some of the violence. There's only one scene that sticks out where a man is shot through the throat but that's really it. The rest of the violence occurs and then you see the people in a pool of blood.
Towards the beginning of the movie, Bruce is injected with a fear toxin. He goes back to the alley where his parents died. Martha and Thomas Wayne are seen briefly laying dead in the alley surrounded by blood. However, Thomas is the only one with a visible bullet wound.