Marvel Cosmic Invasion turns Doctor Doom's castle into a replayable challenge on November 10

Reaching Doctor Doom will take more than clearing a succession of enemy-filled rooms. The Siege of Castle Doom introduces a new structure to Marvel Cosmic Invasion, asking players to navigate a hostile fortress while an increasingly dangerous countdown works against them.

Developer Tribute Games revealed the details on October 26, ahead of the premium DLC's November 10 release. The expansion introduces a run-based mode alongside two new playable characters, Doctor Doom and Invisible Woman.

The Siege Gauge changes the stakes

Doctor Doom's Cosmic Inductor is the central threat. Originally designed to counter Annihilus, the device has become dangerous enough to threaten the entire universe.

The Siege Gauge tracks Doom's growing advantage. Failures increase the pressure, and enemies become more dangerous as the gauge fills. Reaching its maximum before confronting Doom ends the run.

Reed Richards offers a countermeasure called the Stabilizer. Defeating enemies and completing challenges provides batteries that feed the device and support the heroes' upgrades.

This establishes a different rhythm from the standard campaign. Surviving a fight is only part of the challenge; managing resources and selecting opportunities becomes increasingly important.

Five doors, different consequences

Castle Doomstadt presents players with themed doors that influence what happens next. Equipment doors provide offensive or defensive abilities. Events introduce temporary rule changes and possible penalties. Healing doors restore health, while Infinite doors can grant unlimited ammunition or Focus.

Progression doors reward players with batteries for the Stabilizer. Choosing between those options creates decisions about immediate survival and longer-term character strength.

Tribute Games claims the mode contains more than five times as many encounters as the main campaign, excluding additional traps, events and environmental hazards. This is a statement about the announced encounter pool, not evidence that individual runs will last five times longer.

Builds can develop across multiple attempts

The new perk system offers twelve upgrades across offense, defense and tactical categories. Perks are applied separately to individual heroes, encouraging teams to combine different strengths.

That system could complement Cosmic Swap, the original game's ability to alternate between two selected characters during combat. The value of each build will ultimately depend on how strongly the perks influence specific heroes and encounters.

Reed's Lab provides permanent unlocks, including equipment, events and modifiers that can alter future runs. Completing a run also rewards players with a new character color palette.

Cooperative players will see an MVP system highlighting the statistics of particularly effective teammates.

Two new fighters join the roster

Susan Storm brings light manipulation and force-field abilities, while Victor von Doom combines advanced technology with occult powers. Both have appeared in gameplay footage ahead of the expansion.

The fortress itself includes medieval traps, frozen battlements, dangerous elevator platforms and Doom Bots supported by bosses returning from the original campaign.

The Siege of Castle Doom launches November 10, 2026, on PC via Steam, Nintendo Switch, Nintendo Switch 2, PlayStation 4, PlayStation 5 and Xbox Series X|S. The October 26 gameplay announcement did not specify a price.