The upcoming DLC for Marvel Cosmic Invasion, titled The Siege of Castle Doom, will introduce a new game mode that combines classic Beat Em Up combat with evolving mechanics and unique challenges. This mode will be centered around the duality of Reed Richards and Doctor Doom, with the leader of the Fantastic Four guiding the heroes through their ordeal while Doom mocks their efforts to invade Doomstadt.
The Siege of Castle Doom will feature a gauge mechanics system, where a Siege Gauge charges up each time the heroes get bested by enemies within the halls of Castle Doom, while every victory yields batteries charging up a Stabilizer, stalling Doom's progress. The mode will also include new equipment, power-ups, strategies, and player decisions that can change the course of each run in a matter of seconds.