[Guyver Spawn]

The Specter is a pretty dark character, so I would imagine a R rating would work for him. Personally I do feel like Superman does not need a R rated movie. The R rating for the home video release is done as a marketing gimmick to have people to buy the home video release. WB did the same thing by giving The Third Hobbit movie a R rated director's cut on Blu-Ray.

I do feel like The Killing Joke movie needs to be R rated if they want to be faithful to the graphic novel.