Injustice 2 tells the continuing story of an alternate DC Comics universe where, get this, Superman is evil. If you haven't played the first game or read the extensive comics that tell the full story of this universe, let me break it down for you really fast: A few years ago, the Joker did a c-c-combo with hallucination-gas villain Scarecrow to create a kryptonite-infused solution that could affect the normally-impervious Man of Steel. In one of the most egregious fridgings of the modern era, a hallucinating Superman kills pregnant Lois Lane.
Superman's rage then causes him become the most comically evil version of himself possible. While the fantasy of a Superman-gone-wrong has powered official DC works like Red Son (and has created some analogous works in The End League or Irredeemable), the Superman of the Injustice universe is elevated to an entire new level. He opens up by putting his arm through Joker's chest, and the body count just ups from there.
Without spoiling anything in Injustice 2, suffice to say that players make a choice within that game between the two forces at work. Do you prefer Batman, a figure fighting for human liberty free from domination? Or do you think that Superman, a character who literally wants to cover the world in oppressive superbeings who monitor every human to keep them in order, is better?
What's striking about Superman-as-dictator in Injustice 2 is that he isn't merely some kind of analogue for authoritarianism. Superman is the character who cannot fail in his morals. He's synonymous with American ideals of morality, justice, and an unbending will toward a better world for all people. The brilliant turn in the writing of the Injustice games is that Superman can barely see how he's bent from that mission. He thinks he's doing the best for the greatest number. For this Superman, violence against the people you're supposed to protect and represent is just business as usual for someone with as much power as he has.
So in some ways, it's a more brutal critique of the present than it might appear at first glance.