This graphic novel is not a parody, it's an alternate history. A most unusual alt-history: an alternate to a fictional reality, rather than an alternate version of our history. (The most popular themes for alternate history are, What if the South won the Civil War?, and What if the Germans won WWII?)
Alternate history is a concept generally more familiar to those who read SF novels rather than comics/graphic novels. Many of us SF novel readers did read a lot of comics when we were younger, though, and I think this particular graphic novel is aimed at us. We read Superman - and Batman, Green Lantern, Wonder Woman - in the 50's, 60's and 70's. So, although we may not have read any other of this particular series of graphic novels, we have quite a bit of background in the Superman mythos - his real parents, where he grew up, girlfriends, enemies, etc.
I think that knowing that background from the original comics may make this book more enjoyable to my middle-aged generation than to people who are used only to the graphic novels. As well, my generation had the advantage of living through most of the history that was really happening from 1950 on. For those who know the history of the Cold War only from school, many of the details wouldn't make sense. It helps a great deal in reading this book if you are familiar with the course of the Cold War, and that you know not only who JFK was, but some of the celebrity gossip about him as well as the official records. (The name Norma Jean should mean something to you.) You should know what the Warsaw Pact was, and something about in what order the Soviet Union took over various countries.
I liked the way the book involved similar alternate twists on Batman, and brought in Wonder Woman and Green Lantern as well. Batman's hat is the funniest thing I've seen in a while!
A couple quibbles: having the artwork done by more than one artist is distracting; a couple times it was hard to recognize Lois Lane as herself. And I do wish that illustrators would STOP trying to use the Cyrillic alphabet incorrectly. If you can't use the letters for what they really are, don't use them, please. The thing that looks like a backwards R is NOT an R. The letter that looks like a backwards N is NOT an N. So stop it already! Just go for English in the signs and titles, or for accurate Russian. (One illustrator did this correctly, but on many pages, and the cover art, these letters are used incorrectly.) OK, that's one of my pet peeves, since I happen to be able to read Russian a little; it may not bother other people as much as it bugs me.
Summary? A graphics novel that may be of more interest to an older generation that doesn't usually read them, in a vein more familiar to SF readers than comics readers.