Here's a teaser/trailer. I tried a different approach where we just see it from Batman's perspective. The trailer only shows footage from the first half of the film, in order to generate the audience's interest (how's it going to end?!). Deliberately a little thin on details so that people get really curious.
[A teenage boy stands in darkness at enormous statuesque graves, marked MARTHA and THOMAS. Lightning strikes and the boy is smoothly replaced by BATMAN in the shot, in the same pose beside the same grave.]
WAYNE (v.o.)
I've spent the greater part of my life dedicated to the idea that I could rise above mortality.
[BATMAN glides over the city with an extended cape. He folds his wings and begins to dive.]
WAYNE (v.o.)
Through theatrics that feed off the superstition of cowards. But all that I am as Batman--it's all an intricate illusion.
[In the final moments of his dive, he opens the cape and lands, very quietly beside a brick alley. He looks around the corner; several men have cornered a young woman. BATMAN tosses a smoke grenade, which also uses laser light to project a false silhouette of BATMAN in the smoke. A criminal turns to run away from the gas, but finds his peers already incapacitated except for one, who BATMAN holds by the throat from the roof above.]
[Cut to the batcave. The silhouette of WAYNE (head hung low, dressed in the batsuit but with the mask pulled back like a hood) looks across the cave at the silhouette of ALFRED. The cave is an enormous marvel of nature, with a high rugged walls of massive stone and a smooth, polished floor, whose deep blackness reflects the white light like ice. Lights are positioned around the edges of the cave, illuminating various sections enclosed in reinforced glass: a supercomputer with three 80" 4K monitors, a cryptography station, a dedicated chemistry laboratory, an emergency care and recuperation area, a car that's clearly seen a lot of action, and a wall of assorted highly advanced gadgets.]
[Superman flies up the gravity beam and through the World Generator, causing it to explode.]
WAYNE (v.o.)
HE... is not an illusion.
[As he speaks, WAYNE, still in the batsuit across from ALFRED, looks up. He's heavily bearded. He's been in the cave for weeks but hasn't responded to Gordon's requests for help via the bat signal. He's extremely conflicted, tortured and discouraged by the idea that he's barely a flea next to Superman.]
ALFRED (v.o.)
If you fear him, do something. Do something, because if you don't, there's not another person on Earth who can.
[Wayne stares at the screens of the supercomputer, which show buildings crumbling as Superman and Zod tear through them.]
WAYNE
Our greatest monuments... nothing but towers of sand to him.
[Close shot of ALFRED's face, visibly worried about WAYNE, who he's never truly seen so afraid.]
ALFRED
How can BATMAN do nothing?
WAYNE (v.o.)
What can I do, ALFRED, to a god?
ALFRED (in a hushed whisper.)
Build.
[BATMAN and LUTHOR, dressed in similar mech-suits approach SUPERMAN, bloodied and weak and tattered on the ground.]
LUTHOR (furious as he lands a final heavy, bone-breaking punch on SUPERMAN as he tries to rise.)
I DONT BELIEVE, SUPERMAN!
[The screen goes black.]
LUTHOR (v.o., breathless but eerily calm, emotionless)
No. I don't believe in gods.
[Summer 2016]
WAYNE (v.o.)
I've spent the greater part of my life dedicated to the idea that I could rise above mortality.
[BATMAN glides over the city with an extended cape. He folds his wings and begins to dive.]
WAYNE (v.o.)
Through theatrics that feed off the superstition of cowards. But all that I am as Batman--it's all an intricate illusion.
[In the final moments of his dive, he opens the cape and lands, very quietly beside a brick alley. He looks around the corner; several men have cornered a young woman. BATMAN tosses a smoke grenade, which also uses laser light to project a false silhouette of BATMAN in the smoke. A criminal turns to run away from the gas, but finds his peers already incapacitated except for one, who BATMAN holds by the throat from the roof above.]
[Cut to the batcave. The silhouette of WAYNE (head hung low, dressed in the batsuit but with the mask pulled back like a hood) looks across the cave at the silhouette of ALFRED. The cave is an enormous marvel of nature, with a high rugged walls of massive stone and a smooth, polished floor, whose deep blackness reflects the white light like ice. Lights are positioned around the edges of the cave, illuminating various sections enclosed in reinforced glass: a supercomputer with three 80" 4K monitors, a cryptography station, a dedicated chemistry laboratory, an emergency care and recuperation area, a car that's clearly seen a lot of action, and a wall of assorted highly advanced gadgets.]
[Superman flies up the gravity beam and through the World Generator, causing it to explode.]
WAYNE (v.o.)
HE... is not an illusion.
[As he speaks, WAYNE, still in the batsuit across from ALFRED, looks up. He's heavily bearded. He's been in the cave for weeks but hasn't responded to Gordon's requests for help via the bat signal. He's extremely conflicted, tortured and discouraged by the idea that he's barely a flea next to Superman.]
ALFRED (v.o.)
If you fear him, do something. Do something, because if you don't, there's not another person on Earth who can.
[Wayne stares at the screens of the supercomputer, which show buildings crumbling as Superman and Zod tear through them.]
WAYNE
Our greatest monuments... nothing but towers of sand to him.
[Close shot of ALFRED's face, visibly worried about WAYNE, who he's never truly seen so afraid.]
ALFRED
How can BATMAN do nothing?
WAYNE (v.o.)
What can I do, ALFRED, to a god?
ALFRED (in a hushed whisper.)
Build.
[BATMAN and LUTHOR, dressed in similar mech-suits approach SUPERMAN, bloodied and weak and tattered on the ground.]
LUTHOR (furious as he lands a final heavy, bone-breaking punch on SUPERMAN as he tries to rise.)
I DONT BELIEVE, SUPERMAN!
[The screen goes black.]
LUTHOR (v.o., breathless but eerily calm, emotionless)
No. I don't believe in gods.
[Summer 2016]