The greatest challenge Zack Snyder faced with Batman v Superman: Dawn of Justice was figuring out how a human being -- rich, skilled-fighter and highly-intelligent, but lacks superpowers -- could go toe-to-toe with an alien being with god-like powers.
"The advantage that Batman has is the goodness of Superman;" Snyder explained to Total Film. "the compliance to fair lay that Superman has... Batman knows how to exploit Superman." Batman fights dirty!
You can also expect Batman to get his hands on Kryptonite at some point, but he'll still have to rely on an armored suit to take down the Man of Steel, which was created with CGI. Whenever the B-roll footage is released we'll get to see Ben Affleck donning a skintight motion-capture suit that he refers to as "visual effects pyjamas." He thinks of it as "the most humiliating, ridiculous thing in the world," but because they can put the armor on digitally it allowed him to "move freely."
In Batman v. Superman: Dawn of Justice, fearing the actions of a god-like Super Hero left unchecked, Gotham City’s own formidable, forceful vigilante takes on Metropolis’s most revered, modern-day savior, while the world wrestles with what sort of hero it really needs. And with Batman and Superman at war with one another, a new threat quickly arises, putting mankind in greater danger than it’s ever known before.
Batman v. Superman: Dawn of Justice opens March 25, 2016.