Tribute Games and publisher Dotemu have announced MARVEL Cosmic Invasion The Siege of Castle Doom DLC, a premium expansion slated to launch in fall 2026. The upcoming add-on brings Doctor Doom into the fray alongside a new game mode and two additional playable fighters for the arcade brawler.
Quick Facts
- Release Window: Fall 2026
- Platforms: Steam (Windows, Linux), with launch support for Steam Deck
- Key Additions: Doctor Doom, a new game mode, and two playable characters
- Developers: Tribute Games Inc. (developer), Dotemu (publisher)
Doctor Doom Joins the Roster
Doctor Doom sits at the center of the upcoming expansion. While the base game centers on Annihilus and his Annihilation Wave threatening the galaxy alongside villains like Thanos, M.O.D.O.K., and Taskmaster, the new DLC expands the 17-hero roster with two fresh fighters and a dedicated game mode.
The core gameplay continues to lean on the title's Cosmic Swap system. Players pick two heroes before each fight and swap between them during battle to mix skills in fast-paced encounters.
Linux and Steam Deck Support
Dotemu and Tribute Games confirmed that Linux and Steam Deck players are included in the launch plan for fall 2026. The source notes that Steam Deck support is verified, though specific technical details—such as Proton requirements, Vulkan usage, frame rate targets, and battery life data—have not yet been shared by the developers.