Here's why:
* Licensing: The character of Superman is owned by DC Comics, and Warner Bros. Interactive Entertainment had to negotiate separate licensing agreements for each character they wanted to include in the game. It's possible that the rights to Superman were not available at the time.
* Character Roster: The game already featured a diverse roster of DC heroes and villains, including:
* DC Heroes: Wonder Woman, Batman, Green Lantern, Flash, Aquaman, Shazam.
* DC Villains: Joker, Lex Luthor, Brainiac, Harley Quinn, Catwoman, Deathstroke.
While Superman's absence might be disappointing, you can still have fun playing as other powerful characters like Wonder Woman, Shazam, or even Batman (who can use a heat vision-like attack).
If you're looking for a game that features Superman, you might want to try:
* Injustice: Gods Among Us: This game features a robust roster of DC characters, including Superman.
* Lego Batman 2: DC Super Heroes: This game features a more lighthearted take on the DC Universe, with Superman being a playable character.
Have fun playing!