Everything that makes Frank Miller’s art iconic is featured on this cover: fat meaty paws in place of hands, awkward chunky anatomy and the over-use of negative space (or possibly a calculated under-use of color would be more accurate). With a style more recognizable than Jack Kirby’s, Miller knows he doesn’t need all the pieces of the puzzle to tell a story, with bare, trace facts he can build his narrative and make us believe whatever story he'd like.
Superman’s “S” logo, curl and cape are the three traits about him always used to identify the character, and that's all Miller needs--literally nothing else but a body frame is drawn. More time was spent detailing the giant bird claw that is piercing both heroes than on the heroes themselves. It’s about the curiosity of what could kill both of these men, not that they are even characters in the story. They're symbols.
As mentioned in Monique’s post, Miller draws the clawed leg coming from the left side of the image, the beast largely unseen, pulling our eyes slowly to the right. While he uses this trick again to direct us along the picture, his intentions are different, it tells a story in itself, forcing us to ask what the beast is, where it came from, and how did Superman and Green Lantern come to be in it's possession?
Less bad-ass than the majority of his work, Miller's ability to instill fear is showcased here: the horror of the blackened, presumed dead Justice Leaguers close to the center of the page, while the actual events are taking place elsewhere. The best and maybe the most affecting aspect of the image though, is Superman's cape ripped to shreds with and the Green Lantern's ring still glowing from the fight. Even in a single-image, Frank Miller can make the action intense and very real and maintain his balance of the mythic and gritty.