“Heroic Assault is an upcoming gameplay mode that is separate from the main story campaign,” official documentation from the developer reads. “The standalone mode supports up to four players in online co-op and provides a dedicated arena-like environment with specific objectives to complete and enemies to defeat on each floor.”
There are 30 floors to master in total, which should add some longevity to the release. Along the way, you’ll encounter a new threat in the form of “the highly advanced alien lifeform Starro, the Conqueror, as well as the formidable half-human/half-bat hybrid Man-Bat”.
Remember, the main game supports two player co-op already, but this is a separate activity from that, and there are no plans to add four-players to the campaign. Those of you sticking to the two-player mode can try out new Showdown battles, which feature supercharged versions of the game’s main DC Super-Villains, including M. Freeze, Harley Quinn, Clayface, and Talia al Ghul, with brand new legendary gear on the line.