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The Siege of Castle Doom, the second expansion for MARVEL Cosmic Invasion, is scheduled to launch on November 10, 2026. It adds Doctor Doom and Invisible Woman as playable characters, along with a new game mode. Its timing makes it a natural way to build anticipation around Doom ahead of Avengers: Doomsday—but the game’s announcements do not describe the expansion as a film tie-in or cross-promotion.
What’s in The Siege of Castle Doom?
Steam lists The Siege of Castle Doom as MARVEL Cosmic Invasion’s second expansion. The announced additions are:
- Doctor Doom and Invisible Woman as playable characters.
- A new game mode, which has not been described in detail in the announcements cited here.
Steam’s listing says the expansion requires the base game, so it is not a standalone release. The listing also describes it as planned and not yet available. View the Steam expansion listing.
When does the DLC release?
The planned release date is November 10, 2026. Dotemu’s October 8 announcement says the premium expansion launches that day on PC and consoles. The current Steam listing and announcement identify the date; check the relevant platform store for availability and purchase details.
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#1 Best Overall
- 15 PLAYABLE SUPER HEROES: Whether you’re an old-school expert or a first-time fan, you’ll find familiar faces and discover new favourites in a captivating roster of characters from across the Marvel Universe!
- MASTER THE COSMIC SWAP TAG-TEAM SYSTEM: With the Cosmic Swap tag-team system, choose two Super Heroes for each level and switch between them instantly. Create unique combos and powerful special attacks. Each character’s abilities encourage creative team-ups and a more tactical approach to the action.
- AMAZING RETRO ART DIRECTION: MARVEL Cosmic Invasion is a tribute to one of Marvel’s most iconic eras, with stunning full-colour pixel art designs.
- INTUITIVE, FUN MULTIPLAYER FOR EVERYONE: Whether you're teaming up with friends or family, MARVEL Cosmic Invasion has you covered with local/online play and a drop-in/drop-out adaptive system.
Why the timing points toward Doomsday
A Doom-focused expansion arriving in November offers an obvious connection to the anticipation surrounding Avengers: Doomsday. That connection is an editorial interpretation of the timing and character choice, not a stated promotional purpose: the reviewed announcements from Marvel, Dotemu and Steam do not say the DLC was designed to promote the film or announce a collaboration.
What was announced before this expansion?
Marvel said on May 18, 2026, that MARVEL Cosmic Invasion would receive two paid DLC updates during 2026. The second was then described as planned for fall, with a new mode and additional playable characters. The November 10 date and the names of the characters were specified in the later expansion listing and announcement.
Rank #2
- 15 PLAYABLE SUPER HEROES: Whether you’re an old-school expert or a first-time fan, you’ll find familiar faces and discover new favourites in a captivating roster of characters from across the Marvel Universe
- MASTER THE COSMIC SWAP TAG-TEAM SYSTEM: With the Cosmic Swap tag-team system, choose two Super Heroes for each level and switch between them instantly. Create unique combos and powerful special attacks. Each character’s abilities encourage creative team-ups and a more tactical approach to the action
- AMAZING RETRO ART DIRECTION: MARVEL Cosmic Invasion is a tribute to one of Marvel’s most iconic eras, with stunning full-colour pixel art designs
- INTUITIVE, FUN MULTIPLAYER FOR EVERYONE: Whether you're teaming up with friends or family, MARVEL Cosmic Invasion has you covered with local/online play and a drop-in/drop-out adaptive system
Marvel’s May announcement listed PC (Steam), Nintendo Switch and Switch 2, PlayStation 4 and 5, and Xbox Series X|S for its 2026 DLC updates. Dotemu’s October announcement says this expansion is coming to PC and consoles; consult the current store listing for the specific platforms on which it is offered.
Quick Recap
Best Value
- Dual wall insulated: keeps beverages hot or cold
- Stainless Steel, BPA Free
- Leak proof lid with clear slider
Rank #4
- Official Marvel Merchandise
- Marvel Cosmic Invasion T Shirts for Boys, Girls, Men, Women, Kids, Adults; Marvel Cosmic Invasion T Shirts; Cosmic Invasion T Shirts; Marvel Cosmic Invasion; Marvel Games Shirts; Marvel Video Game T Shirts; Marvel 8 bit; Marvel 16 bit; Cosmic Invasion Logo
- Dual wall insulated: keeps beverages hot or cold
- Stainless Steel, BPA Free
- Leak proof lid with clear slider
Rank #3
- 15 PLAYABLE SUPER HEROES: Whether you’re an old-school expert or a first-time fan, you’ll find familiar faces and discover new favourites in a captivating roster of characters from across the Marvel Universe
- MASTER THE COSMIC SWAP TAG-TEAM SYSTEM: With the Cosmic Swap tag-team system, choose two Super Heroes for each level and switch between them instantly. Create unique combos and powerful special attacks. Each character’s abilities encourage creative team-ups and a more tactical approach to the action
- AMAZING RETRO ART DIRECTION: MARVEL Cosmic Invasion is a tribute to one of Marvel’s most iconic eras, with stunning full-colour pixel art designs
- INTUITIVE, FUN MULTIPLAYER FOR EVERYONE: Whether you're teaming up with friends or family, MARVEL Cosmic Invasion has you covered with local/online play and a drop-in/drop-out adaptive system
What to check before buying
- Base game: Steam says it is required to play the expansion.
- Character interest: Doctor Doom and Invisible Woman are the two announced playable additions.
- New mode: A new mode is confirmed, but the cited announcements do not explain its rules or contents.
- Price and platform: The sources cited here do not establish a price. Check your platform’s current storefront for price and availability.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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