It might be pure conjecture -- or at the very least a great deal of happenstance -- but this first issue recalls the cult film Six-String Samurai, which is another post-apocalyptic story that relies on visual flair more than exposition. Specifically, it is a lot of the more zany elements of Six-String Samurai that made their way into Old Lady Harley. While the film didn't have any anthropomorphic squids running a restaurant, it did have a high-speed gumball fight. Yeah, it's that kind of movie.
Side note: If you have't seen this film, do yourself a favor and track it down. It's the most delightful movie about the apocalypse you'll ever see. Guaranteed.
Near the end of the issue, we do see what Gotham City has become -- a neon bastion patrolled by an army of robot Azraels (the reveal felt straight out of The World's End). The empty streets and neon billboards draw their aesthetics from films like Blade Runner and stories about totalitarian futures, like 1984 and The Man in the High Castle.
Harley and Her Zingers
Harley Quinn can't shut up. But then again, this is why so many of us adore her. We mentioned the "Clockjerk Orange" jab earlier, but it doesn't stop there. We get another jab levied at Jean Grey and the The Phoenix Force while Harley is rattling off comic characters who have come back from the dead. Harley and Red Tool also riff on the sci-fi Western series Westworld, which has its roots in dystopian fiction.
But one of the most effective (and long-winded) jokes actually comes from the character Red Tool, who refers to the classic Twilight Zone episode "Time Enough at Last," in which Burgess Meredith is the last man on Earth and finally has time to read his books in peace -- until his glasses break, leaving him essentially blind. Red Tool punctuates the riff by splicing Meredith's role in the episode with his role as the Penguin in the 1960s television adaptation of Batman, when he references Julie "the third best Catwoman" Newmar.
Here's hoping future issues can keep up with the references. There are still plenty of dystopian and post-apocalyptic stories and tropes to riff on. Harley Quinn and Red Tool are perfect for the task, and if Old Lady Harley just becomes a Where's Waldo of picking out the references, that'd be just fine.