When you first load up Harley Quinn's Revenge from its own icon in the main menu for Batman: Arkham City, it comes with a mysterious, grave warning. In short, the events in the DLC take place after the main game, and that events within that DLC are a direct result of Arkham City's mind-shattering ending. I know this seems like a rather bland way to open a review, but I felt it necessary, as trying to properly critique Harley Quinn's Revenge requires some pretty thorough discussion of the story itself. So consider yourself warned and click past the jump…but don't say I didn't warn you.
The Joker is dead, Arkham City has been dissolved, and Batman is nowhere to be found. That's the pretty ballsy start to Harley Quinn's Revenge that almost immediately sets it apart from the previous DLC packs that came before, namely the Nightwing and Robin packs that saw Boy Wonders past and present dropped into Arkham City's Challenge Maps. Harley Quinn's Revenge is a far more story driven affair with a unique twist: for a good-sized portion of the 2 or so hours that you spend on it, you play as Robin, trying to find the MIA Batman in the remnants of Arkham City. It's an interesting twist, even as you wander through the oddly familiar ruins of the Joker's former hideout, solving new puzzles and challenges with Robin's unique abilities. Sure, the free-flowing combat feels virtually the same as Batman's, with Robin's gadget being little more than ornithological analogues for Batman's utility belt. Batarangs are now shurikens, and Batman's pummeling pugilism has been replaced by a multipurpose staff which can sprout a bullet-deflecting shield. It feels just different enough not to feel like a complete retread, but not so alien as to sharpen the game's gentle learning curve.
After a short stint as Robin, you step into Batman's boots for a flashback before once again donning the yellow cape of his sidekick. This goes back and forth a couple of more times before the DLC's conclusion, and for the most part it works. However, there are a few substantial problems with Harley Quinn's Revenge that keep this from being a truly epic epilogue. For one, the foundation that the additional story is built on, the death of the Joker, is a concept so shocking and disruptive that it could have—or should have—had an entire game built off of it. The opening dialogue between Robin and Oracle alone hints at some strange survivor's guilt gnawing at the Caped Crusader, and those are the sort of pathos that really need more time to explore.
Secondly, there's the matter of what the Joker's death means to Gotham City's underworld. Sure, we see that Harley has gone even more off of the deep end, replacing her platinum-blonde locks with a funerary black dye job, and she's trying desperately to maintain control of the Joker's men even as she struggles with her own grief. Unfortunately, that's pretty much the extent of it. The Joker being out of the picture leaves a massive power vacuum in Gotham's criminal element, and the lack of takers trying to pick up his scraps is pretty inexplicable. This idea was explored to great effect in Brian Azzarello's graphic novel Joker, and the lack of even a second-tier villain trying to wrest control from the clearly unhinged Quinn makes this a sadly one-note tale.
The other issue comes from the dramatically decreased size of the territory you explore, which is limited almost completely to the Joker's old hideout. While the story doesn't require the full spread of Arkham City to explore, it is a strangely constricted return to a game whose staggering scope has been reduced to a few city blocks.
After the massive, epic spread of Arkham City, Harley Quinn's Revenge feels more like a stinger setting up the inevitable third Rocksteady Batman game (Arkham State?) than a proper conclusion. It lays down a little groundwork for the ripple effect that Joker's death will have on the Batman universe—at least in the games—but it can't really stand on its own as a must-play follow up.