if you thought Atomic Heart was weird, twisted fun buckle up. At Summer Game Fest 2025, Mundfish pulled back the curtain on their next project: The CUBE, a multiplayer RPG shooter set in the same bizarre alternate-history Soviet universe. And yeah, it looks as mind-bending as it sounds.

Currently in development for consoles and PC via Steam, The CUBE drops players into a massive levitating Rubik’s cube of a world each face and edge shifting and rotating with a logic of its own. Sound confusing? It probably is. But it’s also cool as hell.

Atomic Multiplayer Madness

Unlike Atomic Heart’s solo story, The CUBE is built from the ground up for multiplayer action. You’ll squad up to take on quests, blast through enemy forces, and unravel the mysteries of this sci-fi contraption one rotating edge at a time. There’s loot, progression, and a world that actively shifts beneath your feet literally.

You’ll explore biomes with totally different aesthetics and hazards, each packed with enemies to vaporize and secrets to uncover. And because this is a Mundfish game, expect the strange. Giant floating worms? Creepy talking vending machines? Sentient cubes? All on the table.

Lore, Bosses, and Co-op Chaos

Mundfish says The CUBE will expand the “Atomic Universe” with new characters, lore, and events that both deepen the original Atomic Heart story and set the stage for its future. If you’re a fan of weird fiction, philosophical tech gone wrong, or Cold War dystopias with a modern twist, you’re probably in for a treat.

Combat’s shaping up to be kinetic and customizable think guns, powers, gadgets, maybe some good old fashioned pipe beating. And yes, there are bosses. Big ones. You’ll need teamwork and good builds to survive the toughest challenges this mad world throws at you.

When Can We Play?

No release window yet, but the game is confirmed for consoles and PC via Steam. Given the scope of the concept and what we’ve seen so far, this one’s probably still cooking for a bit. But hey, if it ends up being as wild and weirdly playable as Atomic Heart, it’ll be worth the wait.

We’ll keep our eyes on this one and update you with every twisted turn of The CUBE. Stay tuned to 1-Up Games!