In the middle of April, we started hearing increasingly concrete details about a possible expansion to critical darling, and blockbuster selling, caped crusader follow-up, Batman: Arkham City. Initially thought to be centered around a playable Robin mission, then teased as a Harley Quinn-centric story beat, it has now been confirmed that both rumors were actually true.

In the “Harley Quinn’s Revenge” expansion, players will take-on the role of Robin, presumably to rescue Batman from the clutches of Jokers number one gal, Dr. Harleen Frances Quinzel. While details on the add-on are still slim, Rocksteady Studios has released a brief teaser for “Harley Quinn’s Revenge” – which mostly relies on tracing the curves of the fan-favorite villainess (check it out at the top of the page).

The new teaser is basically a condensed version of the footage we already saw in the Batman: Arkham City Game of the Year Edition trailer – i.e. Harley surprising “B-Man” – except this time interested gamers don’t have to sit through teases for DLC packs they already own. That said, if you’ve yet to pick-up Batman: Arkham City, the Game of the Year Edition is certainly worth a look – and features plenty of worthwhile bonus content.

While the teaser trailer offers very little in the way of insight into the actual DLC gameplay, since it mostly just provides players with a drawn-out look at Harley’s CGI lady-frame, Rocksteady has also revealed new screenshots from the expansion – featuring a batch of new thug designs as well as the Boy Wonder, Robin, in action.

Check out the new screenshots below:

Even the Robin images are somewhat underwhelming – considering many players have already tested out Tim Drake’s fighting moves as a playable character in his respective DLC challenge rooms. That said, the focus on Robin in the images certainly hints that gamers will be playing as the character a lot in “Harley Quinn’s Revenge” – which, as we’ve speculated before, could indicate that the expansion story follows the capture and subsequent rescue of Batman from Harley’s vengeful clutches.

Here’s the official word from Rocksteady:

Payback’s a bitch, especially when dealing with The Joker’s most psychotic sidekick, Harley Quinn. Harley is the new boss of Arkham City and is determined to make Batman pay for what he’s done to The Joker. The Harley Quinn’s Revenge mission sends players back into Arkham City to face their final challenge as they interchange between playing as both Batman and Robin.

According to the press release, “Harley Quinn’s Revenge” will add about two hours of “fresh single-player gameplay” – though, until we know the actual cost of the add-on, it’s hard to determine whether or not the experience will justify money spent (especially after an, arguably, thin bonus Catwoman chapter).

Follow me on Twitter @benkendrick for further updates on Batman: Arkham City as well as other movie, TV, and gaming news.

The Batman: Arkham City Game of the Year Edition and Harley Quinn’s Revenge DLC are set for release May 29th on the PS3 and Xbox 360.