Atomic Heart II will build on the IP's RPG elements, while The Cube brings a new multiplayer dimension to its retrofuturistic world.
Mundfish is expanding its retrofuturistic sci-fi universe in a big way. During Summer Game Fest 2025, the studio revealed not one but two major projects: a full sequel, Atomic Heart II, and a brand-new multiplayer experience called The Cube. Both titles will continue the alternate-history narrative introduced in the original Atomic Heart, which has now attracted more than 10 million players worldwide.
Atomic Heart II expands the story on a global scale
Picking up after the events of the first game, Atomic Heart II drops players back into a world on the brink of collapse. Once a utopia powered by robotics and AI, the setting has descended into chaos no longer confined to a single facility, as the story now stretches across the globe.
Described as an action-adventure RPG with open-world elements, the sequel introduces an expanded combat system, deeper RPG mechanics, and an emphasis on player choice. You’ll once again wield a mix of glove-based abilities and both melee and ranged weapons, with more flexibility to experiment with different combat styles.
Mundfish promises a richer, more immersive world with returning characters, new faces, and a mystery that digs deeper than ever before. Built using Unreal Engine, the game leans heavily into dystopian aesthetics and draws inspiration from titles like BioShock, Control, Cyberpunk 2077, Metro Exodus, and Dying Light. Expect narrative depth, dynamic side quests, and more interactive environments, all set within a reimagined alternate history.
The Cube brings reality-bending chaos to multiplayer
Also announced during Summer Game Fest 2025, The Cube is a standalone MMO spin-off set several years after Atomic Heart. At its centre is a strange, levitating megastructure known only as the Cube, a force that has triggered strange phenomena around the world. With reality itself under threat, players must explore its depths and uncover the secrets hidden within.
Unlike the story-driven structure of Atomic Heart II, The Cube takes a more experimental, multiplayer-first approach. Environments constantly shift, new enemies appear, and hidden objectives are scattered throughout its impossible geometry. According to Mundfish, the Cube contains an equation capable of reshaping reality, and if players fail to solve it, the human race may not survive.
Progression in The Cube is designed to be persistent, even in failure. It’s a bold direction for the franchise, blending MMO mechanics with the surreal, science-fiction horror the series is known for.
Neither Atomic Heart II nor The Cube have a confirmed release date yet, but both titles are in development for PC, PlayStation 5, and Xbox Series X/S.
