I got another idea for a game, how about the main story arc is that someone, Probably Lex Luthor, finds a way to turn the sun's rays red or block out the rays that give Superman his abilities. Or something along those lines. The point being it de-powers the Man of Steel. He wouldn't be completely powerless, he still has enough energy stored in his body to be super human, but weak enough to where Superman is much more vulnerable than he normally is. Some of his powers are failing him, he progressively shows signs that he is losing his powers. The point of the game is to try and stop Luthor in his plans and this is made even more difficult because a roster of Superman villains are in on this knowing that Superman is vulnerable.