Superhero games, for one reason or another, fall into two categories. The first is the beat-'em up. These are the type of games that you find in pizza joints and bars. They're the Teenage Mutant Ninja Turtles arcade games of the world. They're simple, linear and fun if you don't mind repetitive gameplay and boring level design.
The other group is the open-world game, which sometimes works but most of the time doesn't. When Spider-Man does it, the sandbox gameplay feels right. On the other hand, it's never felt right for Superman.
The problem with these projects is that they feature the heroes, but they don't necesarily capture the essence of their powers and what they do. How do you make a game that makes you feel faster than a speeding bullet? How do you create a title that has the team dynamic of the X-Men?
As disappoitning as superhero games can be, that could change with Batman: Arkham Asylum. This may be the first time a Dark Knight game actually makes players feel like the Caped Crusader.