Tribute Games has revealed new gameplay details for Marvel Cosmic Invasion: The Siege of Castle Doom, the beat-’em-up’s second DLC expansion launching November 10, 2026. The expansion introduces a replayable game mode featuring branching routes, upgradeable abilities, environmental hazards and two additional playable characters: Invisible Woman and Doctor Doom.
In an October 26 PlayStation Blog post, Tribute Games level designer Kevin Chiasson explained how the new mode expands the game’s traditional side-scrolling combat with strategic decisions and progression systems. Players will fight through Doctor Doom’s castle while managing competing gauges that influence their chances of completing each run.
The mode takes place in Castle Doomstadt during the Annihilation Wave, with Reed Richards guiding the heroes through the fortress while Doctor Doom attempts to stop their advance. Doom is charging a device called the Cosmic Inductor, which threatens to grant him extraordinary power.
Two interconnected systems govern the experience. The Siege Gauge increases whenever heroes are defeated by enemies, while successful encounters provide batteries that contribute toward Reed Richards’ Stabilizer Gauge. Collecting enough batteries allows players to create Stabilizers that delay Doom’s progress and support their team’s development.
Unlike the main campaign’s more straightforward progression, The Siege of Castle Doom introduces multiple routes through the fortress. Players select themed doors that determine which challenges, rewards or opportunities they encounter next.
Equipment doors provide special abilities, including force fields and powerful energy attacks. Event doors lead to arenas with temporarily altered rules, potentially rewarding or penalizing players depending on their performance. Heal doors restore health, while Infinite doors can grant unlimited ammunition or focus. Progression doors award a random quantity of batteries for the Stabilizer Gauge.
Tribute Games says the new mode contains more than five times as many encounters as the main game, excluding its additional events, traps and environmental hazards.
The castle itself features several distinct challenges. Players will navigate medieval torture devices in the Halls of Doom, freezing blizzards across the Castle Battlements and dangerous elevator platforms inside the Tower of Solitude, where Doom conducts his experiments.
Character development also plays a larger role in the expansion. As players gather Stabilizers, Reed Richards can improve individual heroes through a branching Perks system divided into Offense, Defense and Tactical categories.
Each character receives their own upgrades, allowing players to develop different abilities across the team. This creates opportunities to combine complementary builds rather than relying entirely on the characters’ starting move sets.
Multiplayer sessions will also introduce an MVP system that highlights the most effective participants through their performance statistics.
Between encounters, players can visit Reed Richards’ laboratory to expand their available options. The lab provides additional unlockables, including equipment, events and modifiers that change subsequent runs through Castle Doom. Completing a run also unlocks a new color palette for the selected hero.
The expansion’s two playable additions were originally confirmed by publisher Dotemu and developer Tribute Games during New York Comic Con on October 8.
Invisible Woman, also known as Susan Storm, brings light-manipulation powers and defensive force-field abilities to the roster. Doctor Doom joins with advanced technological armor and abilities drawing on his knowledge of the occult, allowing players to control the expansion’s central antagonist.
The Siege of Castle Doom follows the game’s first DLC, which added Cyclops and The Thing as playable characters in May 2026.
The new expansion is scheduled to launch November 10 for PC through Steam, PlayStation 4, PlayStation 5, Nintendo Switch, Nintendo Switch 2 and Xbox Series X|S. It is a paid add-on requiring the base game.
With its branching encounters, character-specific progression and unlockable modifiers, Castle Doom introduces a different structure from Marvel Cosmic Invasion’s main campaign, giving players multiple ways to approach subsequent runs.
