It's interesting to note that, although Igor was not a character in Mary Shelley’s book, Max Landis had chosen to tell the Frankenstein story through Igor's eyes. That decision could have cost the movie a lot since it made Victor Frankenstein a secondary character rather than the primary one.
Unfortunately Radcliffe's committed portrayal of the hunchback, and even McAvoy's madman moments could not have saved this film from certain death in the big screen. One fascinating thing that may have derailed the movie from its chosen Victorian-era scary course is the introduction of a love interest. Igor's interest in a brunette circus performer seemed insincere compared with the chemistry between Igor and Victor Frankenstein himself. And the introduction of a rich benefactor in the form of an androgynous-looking, blonde medical student didn't help the movie from seeming homoerotic. It's comical, and keeps moviegoers' attention from the dark message of the film.
