Development Hell/Stillborn Franchise: The film was supposed to get a sequel, yet everyone involved in it got so busy that the producer has since said the movie "will not happen any time soon if at all." James McAvoy then admitted that while he is still interested, the time in development hell and the studio's struggles to find a suitable script are all red flags.
Dyeing for Your Art: James McAvoy worked out to improve his physique for the film's action scenes, and suffered several injuries during shooting, including a twisted ankle, and an injured knee.
You wouldn't expect a slim, 5'7", non-macho actor be the star of an action movie, but James McAvoy got to do just that.
Playing with Character Type: Freeman initially appears to be playing the same kindly, wise old man character he always plays. Turns out he's the villain.
Production Posse: As the movie was produced by Timur Bekmambetov, Konstantin Khabensky appearing in it in some capacity was pretty much a given. When the movie was released in Russia, a popular joke was that the entire movie was made just so that Khabensky would see Angelina Jolie naked.
What Could Have Been: The comic started life as a rejected pitch for an Elseworlds featuring the Secret Society of Super-Villains. Elements of this are still visible, such as basically the entire cast being Expies of various DC villains and heroes.