Cosmic Invasion: Siege of Castle Doom Reveals New Mode Ahead of November 10 Launch
Doctor Doom is preparing to unleash a weapon that could destroy the cosmos, and Marvel's heroes are running out of time to stop him.
Developer Tribute Games and publisher Dotemu have released a new gameplay trailer for MARVEL Cosmic Invasion: The Siege of Castle Doom, offering a closer look at the new run-based game mode arriving with the premium DLC on November 10, 2026.
The expansion introduces Castle Doom, a replayable challenge built around branching routes, powerful upgrades, dangerous encounters, and a race against time. Players will also gain access to two new playable characters, Susan Storm (Invisible Woman) and Doctor Doom, alongside additional cosmetics and music.
The announcement comes as MARVEL Cosmic Invasion has reached more than 1.5 million players.
Storm Castle Doom Before It's Too Late
The new Castle Doom mode sends players into Victor von Doom's heavily defended fortress to stop his latest invention, the Cosmic Inductor.
Originally designed to counter the threat posed by Annihilus, Doom's creation has become a danger to the entire universe.
Players must fight through the castle's defenses and reach Doom before the weapon can be activated.
Unlike the game's traditional campaign structure, Castle Doom uses a run-based format where each attempt presents different challenges, rewards, and opportunities to improve the team's abilities.
Players can choose routes through the fortress, encounter powerful enemies, and collect upgrades that change how their heroes perform in battle.
The goal is to survive long enough to confront Doom while becoming powerful enough to defeat him.
The Siege Gauge Makes Every Second Count
One of the most important mechanics in Castle Doom is the Siege Gauge.
As players progress through the fortress, the gauge gradually fills, increasing the strength of Doom's forces.
Enemies become more dangerous as the siege continues, making it increasingly difficult to survive.
If the gauge fills completely before players reach Doctor Doom, the run ends immediately.
This creates a constant balance between exploring for upgrades and moving quickly enough to finish the mission.
Taking additional routes could provide useful rewards, but spending too much time searching for improvements may give Doom the advantage.
Reed Richards Helps Players Fight Back
The Fantastic Four's Reed Richards has created a device called the Stabilizer, designed to counter Doom's Cosmic Inductor.
Players charge the Stabilizer by surviving encounters and collecting Battery Cells throughout the castle.
These resources can be used to unlock improvements across three categories: offense, defense, and tactical abilities.
There are 12 different perks available, allowing players to modify their heroes' combat capabilities.
Depending on their choices, players can strengthen damage output, improve survivability, or gain tactical advantages that help them handle tougher encounters.
The perk system gives players an opportunity to experiment with different combinations and build strategies around their favourite Marvel characters.
Challenges Can Reward or Punish Players
Castle Doom is filled with optional challenges that offer opportunities to earn additional rewards.
Successfully completing these encounters can help players become more powerful, but failure comes with consequences.
Some challenges apply negative effects to the player's fighters when objectives are not completed.
Doctor Doom has also prepared traps throughout his fortress, adding another layer of danger to exploration.
Alongside Doom Bots, players will face returning enemies and bosses from the original MARVEL Cosmic Invasion campaign.
These encounters should make Castle Doom feel familiar to returning players while introducing a different challenge through its progression systems and time pressure.
Permanent Upgrades Encourage Multiple Runs
Castle Doom also features long-term progression through Reed's Lab.
As players complete runs and gather resources, they can permanently unlock additional equipment, events, and modifiers.
These rewards can influence future attempts, giving players more options when returning to the fortress.
Modifiers can also increase the difficulty of subsequent runs while offering opportunities for greater rewards.
That progression system is designed to make repeated playthroughs worthwhile, even when players fail to defeat Doctor Doom.
It also introduces a different style of replayability to MARVEL Cosmic Invasion, combining its arcade-inspired beat 'em up combat with systems commonly associated with roguelite games.
Susan Storm and Doctor Doom Join the Playable Roster
The Siege of Castle Doom also introduces two new playable characters from the Fantastic Four universe.
Susan Storm, also known as Invisible Woman, joins the roster with abilities based around invisibility, force fields, and manipulating light.
Her powers bring a different combat style to the game, adding defensive and offensive possibilities to the existing tag-team system.
Doctor Doom also becomes playable, giving players access to his advanced technological armour and mystical abilities.
Doom's combination of technology, intelligence, and occult powers makes him a distinctive addition to the roster.
Both characters expand the possibilities of the game's Cosmic Swap system, which allows players to switch between two selected heroes during combat and combine their abilities.
New Colour Palettes and Music From Tee Lopes
In addition to the new characters and game mode, the DLC introduces additional cosmetic rewards.
Players who successfully defeat Doctor Doom can unlock new colour palettes for their playable superheroes.
These rewards give players another incentive to complete runs with different characters.
The expansion also includes new original music from Tee Lopes, whose work has helped define the retro arcade-inspired sound of several modern games.
His return continues the game's celebration of classic Marvel comics and arcade-era action.
MARVEL Cosmic Invasion Continues to Grow
MARVEL Cosmic Invasion originally brought together 17 playable superheroes in an arcade-style beat 'em up inspired by Marvel's classic comic book eras.
The game follows Earth's mightiest heroes and cosmic defenders as they unite against Annihilus and his devastating Annihilation Wave.
Players can switch between two characters during combat, combining attacks and abilities while battling familiar Marvel villains.
The Siege of Castle Doom builds on that foundation with a different type of challenge.
Rather than focusing entirely on progressing through traditional stages, the new mode emphasizes player choice, character builds, permanent unlocks, and repeated attempts.
For players who have already completed the main adventure, Castle Doom offers a new reason to return.
When Does The Siege of Castle Doom Launch?
MARVEL Cosmic Invasion: The Siege of Castle Doom launches November 10, 2026, for:
- PC via Steam
- Nintendo Switch
- Nintendo Switch 2
- PlayStation 4
- PlayStation 5
- Xbox Series X|S
The expansion is premium downloadable content and requires the base game.
Final Thoughts
The Siege of Castle Doom looks like a meaningful expansion for MARVEL Cosmic Invasion.
The new mode takes the game's already entertaining tag-team combat and places it inside a more demanding structure built around strategy, progression, and risk.
The Siege Gauge creates tension by forcing players to balance exploration against the threat of running out of time, while the Stabilizer and perk systems allow players to develop different combat builds during each run.
Permanent unlocks through Reed's Lab should also give players reasons to revisit the fortress even after completing it successfully.
Adding Susan Storm and Doctor Doom to the roster is another welcome addition, particularly for Fantastic Four fans.
With a new game mode, additional characters, cosmetics, and music, The Siege of Castle Doom could be one of the most substantial reasons yet to return to MARVEL Cosmic Invasion.