The 2006 movie Superman Returns was supposed to reignite the comic-book character for big-screen audiences and make a star out of unknown actor Brandon Routh. While critics praised the film, it underwhelmed at the box office, earning $391 million worldwide.

Now, with another Superman film in the works -- Zack Snyder's Superman: Man of Steel, which stars Henry Cavill in the title role -- Superman Returns director-producer Bryan Singer is admitting that he made some mistakes with his own film.