The problem: Batman punching Superman in the face (and vice versa) is a compelling image, and one that has spawned a number of fighting games, crossover comics, and an upcoming movie starring that guy from Phantoms, but there’s always an inconsistency with the powers. Batman can withstand a punch from Bane, but Superman can explode mountains with an errant sneeze. The appeal of a fighter like Injustice is seeing Supes cut loose and punch his fellow caped crusaders into outer space, but how can he do that without immediately killing someone?
The solution: Other crossover games, like Marvel Vs. Capcom, would just ignore the inconsistency, but Injustice is so story-heavy there needs to be some reason for it. Enter the 5-U-93-R pill. Invented by Lex Luthor, the supplement toughens up anyone to near-Superman levels of durability, placing everyone on an equal playing field. It was meant to only assist the Justice League, but Batman and The Joker got their hands on the pills, it put all the fighters on the same level, allowing non-murderous heroes to cut loose on their now-unkillable opponents. Oh well, we suppose that excuse is still better than Mortal Kombat Vs. DC Universe's explanation of "it's magic!"