Dotemu and Tribute Games have announced The Siege of Castle Doom, a Doctor Doom DLC pack for Marvel Cosmic Invasion with a new mode and two playable characters, but price, date, and roster details remain under wraps.
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Castle Doom is the next destination for Marvel’s arcade brawler
Dotemu and Tribute Games have revealed The Siege of Castle Doom, a new Marvel Cosmic Invasion DLC release built around Doctor Doom, and the biggest confirmed hook is also the biggest unanswered question: the expansion adds an all-new game mode, but the publisher and developer have not yet said how that mode works.
According to Polygon, Tribute Games and Dotemu announced the paid DLC on Monday, describing it through a news release as a Doom-centered addition that will arrive with two new playable characters. NintendoEverything also reports that the Siege of Castle Doom DLC will feature a new game mode and two playable characters, with Doctor Doom central to that mode. Both outlets say more information is being held for a later date.
For a Marvel beat em up that already leans on tag-team momentum, that lack of mechanical detail is the story. Marvel Cosmic Invasion is not a slow-drip RPG expansion where a famous villain can carry the promise alone. Its appeal lives in screen control, enemy waves, readable co-op chaos, and the rhythm of swapping heroes mid-fight. A Doctor Doom DLC can sell itself on castle iconography and supervillain theater, but beat ’em up fans should be watching for the shape of the mode, the utility of the new characters, and whether Castle Doom changes the pace rather than simply repainting the arena.
The DLC is currently announced for fall 2026. Polygon reports that a specific date and price have not been shared.
The confirmed package is small on paper, but potentially structural
The confirmed content list for The Siege of Castle Doom is narrow: one new game mode, two new playable characters, and Doctor Doom at the center of the setup. That is all Dotemu and Tribute Games have publicly put on the table through the reports provided. The identity of the two playable characters has not been announced. Polygon specifically notes that the companies have not said whether Doom himself will be playable.
That distinction matters because the phrase Marvel Cosmic Invasion Doctor Doom will lead many players to the same assumption: if Doom is on the key art and the mode bears his castle’s name, maybe he is one of the two fighters. At this stage, that remains unconfirmed. The safe reading is that Doom is central to the DLC’s mode, not necessarily part of the playable roster.
The base game’s structure gives the additions more weight than a simple headcount. NintendoEverything’s overview describes Marvel Cosmic Invasion as a star-spanning brawler against Annihilus and the Annihilation Wave, with players choosing from a roster of 17 Super Heroes and tagging between duos mid-fight through the Cosmic Swap system. Wikipedia’s gameplay summary similarly describes a side-scrolling arcade beat ’em up where each player selects two characters and can switch between them during combat.
That means every new fighter has to solve two problems. They need to feel distinct when controlled directly, and they need to create useful pairings when swapped in alongside the existing cast. Before launch, the most useful reveal would be footage showing how the two characters handle crowds, bosses, vertical space, and assists inside the Cosmic Swap framework.
Doom arrives after the first roster expansion tested the format
Polygon reports that The Siege of Castle Doom is Marvel Cosmic Invasion’s second DLC, following a character pack released earlier in the summer that added Cyclops and The Thing. That prior release is an important reference point because it shows the post-launch plan has already moved beyond the launch cast and into targeted Marvel-era additions.
There is a small roster-count wrinkle across the available sources. Wikipedia says Marvel Cosmic Invasion launched with 15 characters on December 1, 2025. NintendoEverything’s current overview says the game has a playable roster of 17 Super Heroes. Polygon’s account of Cyclops and The Thing joining earlier in the summer explains how those numbers line up if the current roster count includes the first DLC characters, but the sources themselves frame the figures differently: launch roster versus current overview.
That matters for Siege of Castle Doom because the next two characters will enter a game that has already absorbed one paid roster bump. Polygon lists the first DLC characters as Cyclops and The Thing, while also noting that the wider roster includes staples like Spider-Man and Wolverine alongside less obvious picks such as Phyla-Vell and Beta Ray Bill. The mix has been one of Cosmic Invasion’s selling points: familiar cover stars beside cosmic deep cuts.
For Doom, the natural expectation is Fantastic Four adjacency, Latverian menace, or cosmic-scale power. Expectation is not confirmation. Until Dotemu and Tribute Games name the fighters, the better question is whether the pair broadens the game’s combat language. A heavy bruiser, a trap-setter, a flight-focused zoner, or a technical hybrid would each change the co-op chemistry in different ways.
A Doom mode has to earn its castle
Doctor Doom is an unusually strong fit for a beat ’em up expansion because Castle Doom implies a clear spatial fantasy. Corridors, throne rooms, machinery, traps, armored guards, and boss escalation all suit the genre’s old arcade grammar. That is interpretation based on the title and character, not announced stage design. Dotemu and Tribute Games have not yet described the mode’s level structure, enemy lineup, bosses, or objectives.
What is confirmed is that Doctor Doom will be central to the new mode. NintendoEverything calls the focus unsurprising and connects the spotlight to the upcoming Avengers: Doomsday movie. Polygon places the reveal in a broader 2026 Doom moment, noting the character’s coming role in Avengers: Doomsday and a separate appearance leading a team in Marvel Tokon: Fighting Souls. Those connections help explain the timing, but they do not tell players how Siege of Castle Doom plays.
That is the gap beat ’em up fans should keep their eyes on. Marvel Cosmic Invasion’s main campaign, as described in NintendoEverything’s overview, is built around Annihilus attacking across the galaxy and heroes fighting through the Annihilation Wave while Thanos, M.O.D.O.K., Taskmaster, and other allies support the larger threat. A Doom-centered mode could be a side story, a challenge gauntlet, a remix mode, or a separate campaign-style run. None of those formats has been confirmed.
The strongest version of this DLC would use Doom as an encounter designer, not only as a marquee villain. In a brawler, a castle is only as memorable as the pressure it applies: enemy placement, stage hazards, boss reads, and co-op recovery windows. The reveal has the right silhouette. The next trailer needs to show the tempo.
Platforms, price, and older-system support remain unsettled
The confirmed release window is fall 2026. Polygon reports that Marvel Cosmic Invasion: The Siege of Castle Doom will be released for Nintendo Switch, Nintendo Switch 2, PlayStation 5, Windows PC, and Xbox Series X. NintendoEverything, covering the announcement through its Nintendo platform focus, says Marvel Cosmic Invasion is available on Switch 2 and Switch.
There is a platform question around systems outside Polygon’s DLC list. Wikipedia’s entry for the base game says Marvel Cosmic Invasion released on Linux, Nintendo Switch, Nintendo Switch 2, PlayStation 4, PlayStation 5, Windows, and Xbox Series X/S on December 1, 2025. IGN’s game page also lists the initial release as December 1, 2025, though the provided IGN text does not present a full platform list. Because Polygon’s Siege of Castle Doom report does not name PlayStation 4 or Linux for the DLC, support on those versions should be treated as unannounced based on the provided material.
Price is also unannounced. Polygon calls Siege of Castle Doom paid DLC, but says the price was not shared. That leaves practical purchase questions open: whether the DLC is sold standalone, bundled with prior content, included in any pass, or discounted for existing owners has not been specified in the supplied sources.
IGN’s page lists Marvel Cosmic Invasion with “In-Game Purchases” in its content rating information, which is consistent with a game that can support add-on content, but it does not answer the pricing model for this particular release. Players who care about platform parity, family accounts, or cross-generation access should wait for store listings or a publisher FAQ before buying ahead of the DLC window.
What to watch before launch if you play for co-op rhythm
The safest advice for beat ’em up fans is to wait for gameplay footage before judging the Marvel Cosmic Invasion DLC. The name Siege of Castle Doom carries obvious Marvel weight, and Doctor Doom gives the expansion a strong dramatic spine, but this genre lives or dies on contact: hit stun, crowd flow, boss clarity, invincibility windows, and whether four-player co-op stays readable when powers cover the screen.
The base game has enough goodwill to make the DLC worth tracking. Polygon reports that Marvel Cosmic Invasion currently holds an 84% Critics Recommend score on OpenCritic. IGN rated the game 7 out of 10, calling it “good” and writing that “the stages and enemies aren’t going to blow you away, but Marvel Cosmic Invasion’s tag team action still has the juice.” IGN’s page also lists local four-player multiplayer and online four-player multiplayer, while HowLongToBeat data shown on IGN puts the main story around four hours, story plus sides around six hours, and completionist play around twelve hours.
That context sets the bar for Siege of Castle Doom. If the original strength is tag-team action and replayable co-op rather than spectacular stage variety, then an all-new mode has to prove it adds durable reasons to return. New characters alone can refresh a roster for a weekend. A smart mode can keep a brawler in rotation.
Before launch, watch for four details: the identities of the two playable characters, whether Doom is playable or strictly the mode’s central villain, the mode’s structure, and the final price. Those are the facts that will determine whether this Doctor Doom DLC is an essential return trip to the arcade cabinet or a wait-for-sale add-on for casual Marvel fans.