Batman gains an ally in Bane.

Could there possibly be a better game for Halloween time than “Batman: Arkham City”?

Nearly everyone is wearing a costume, a mask or makeup, and a terrifying, nearly invisible monster stalks a dilapidated section of Gotham City.

That would be Batman himself, of course.

Captured by the evil psychiatrist Hugo Strange, who knows Batman is Bruce Wayne, the Caped Crusader finds himself tossed into the no-man’s land of Arkham City, a walled-off section of Gotham that, with Blackgate Penitentiary and the old Arkham Asylum out of commission after the events of 2009’s “Batman: Arkham Asylum,” has been made into a ghetto for Gotham’s inmates and undesirables, from political prisoners to insane murderers, with helicopter patrols keeping tabs on what’s going on inside.

The only rule is: Don’t try to escape. Beyond that, imprisoned super-criminals such as the Joker, Two- Face and Penguin have been free to carve out fiefdoms and wage their gang wars within the boundaries of the prison. There’s no shortage of firearms and other weapons, and goons laugh about the murders, tortures and other atrocities they’ve committed.

It’s not a nice place to be.

Batman could get out, but he’s not interested in escape. Strange is up to something sinister, and Batman means to find out what. Along the way he’ll rescue Catwoman from Two-Face, confront the Joker, track down a serial killer who keeps calling public phones for Batman to answer, and work with former enemy Bane to destroy barrels of a dangerous drug from the last game, among other missions obligatory and optional.

There is no shortage of things to do, from missions like the ones above to the hundreds of challenges the Riddler has placed around town.

Counter to the focused progression of “Arkham Asylum,” which unlocked areas gradually as Batman found new pieces of equipment, “Arkham City” is much more open from the beginning. It’s not fully so — some obstacles can only be passed with the right tools. But Batman can swing and glide from one end of the enclave to the other from the very start.

At times Batman must venture into buildings and underground, and it’s necessary to find vantage points above or below the armed goons patrolling these areas — fast and fit as he is, enough bullets will still take down the Dark Knight.

The combat expands upon the foundation laid down in “Asylum” — just a few button combinations are used to make Batman fight anything from single foes to whole mobs, with proper timing of attacks and dodges being the key to victory. Defeating foes earns experience levels that can be applied toward unlocking new skills and upgrading equipment, while certain missions introduce new gadgets and abilities for Batman to employ.

Apart from Batman’s adventure, new copies of “Arkham City” include a code to download a second campaign in which you play as Catwoman in a quest for stolen valuables. The game switches to this side story from time to time, and the download includes challenge maps to accompany those available for Batman.