A fighting game you play for the plot.
Who would win in a fight? Comics writers know this is what fans argue about, endlessly, and feed those arguments with crossovers and stories like Batman vs. Superman. Usually it’s naff stuff where characters just biff each other for a bit and then abruptly form a getalong gang as if they weren’t battering each others’ faces in just five minutes ago.
The developers of Mortal Kombat obviously weren’t going to do anything so weaksauce. In the Injustice games, Superman’s gone full evil and started a tyrannical regime straight-up called The Regime, which Batman leads a resistance against. The inciting incident of the whole storyline kills off Lois Lane and the Joker, and it gets wilder from there. By the time of Injustice 2, Superman has been imprisoned for his crimes, Clock King’s had his daft head blown up, Green Arrow’s been killed and replaced by a version of himself from a dimension where his wife died instead, and Gorilla Grodd’s taken over Gorilla City in a bloody coup. Take that, Zack Snyder.
All that stuff is only relevant in story mode, of course, and story modes aren’t normally the reason people play fighting games—excepting Tekken’s agreeably insane one, with people throwing their family members off cliffs or into volcanos, hurling motorbikes at helicopters, and fighting bears. Usually though, fighting games struggle to tell a coherent story because they’ve got so many characters to work with.
