Film-Noir Cartoon Fantasy
Robert Zemeckis describes Roger Rabbit as being three, three, three films in one. No wonder it had the budget of three films at the time.
According to Zemeckis, it was "a period film-noir live-action movie, it was a feature-length animated movie, and it was a special effects movie." (Source)
Like Russian nesting dolls, it is all these things, one inside the other. The most dominant genre is film noir. Eddie Valiant is our detective with a drinking problem, a dark past, and a heart of gold. Dolores is Eddie's put-upon Girl Friday who doesn't get nearly enough appreciation for the work she does. Roger Rabbit is his client who may or may not be telling the truth. And Jessica Rabbit is a femme fatale whose body isn't the only thing that's killer.
The fact that half of these characters are cartoons adds the film's fantastic absurdity. And we mean "fantastic" in the sense that the root word is "fantasy." Who didn't grow up watching cartoons as a kid and wish she could meet Mickey Mouse or Bugs Bunny?
With its weird combo of genres, Roger Rabbit appeals to kids and adults alike. And of course it appeals to all of us who are just overgrown children.