His portrayal in The Dark Knight Returns may not have been the most flattering, nevertheless, Superman played a key role in the story as a prime antagonist to Batman.
I don't know, maybe the over the top symbolism was supposed to play as parody, but the image of the Man of Steel holding a bald eagle with an unbuttoned shirt was a bit much in the film. Nevertheless, it really played up the boy scout interpretation of Supes.
On the other hand, Superman was portrayed as quite powerful, withstanding and recovering from a nuclear detonation which temporarily zombified him.
Of course, the highlight of the movie was the physical showdown between the World's Finest. The film also included an Easter Egg of the iconic Chris Reeves Superman poster in the background of the brutal beat-down. I guess if Superman had to lose a fight, who better to lose to than Batman?
Check back next week for another chapter in The Super History of Superman.