When Does The CUBE Come Out? Atomic Heart's MMO Shooter

Atomic Heart turned Mundfish from an unknown studio into the owner of one of the strangest worlds in modern shooters, and the team has not wasted the momentum. Of the projects it unveiled in June 2025, The CUBE is the one players will get their hands on first. Mundfish CEO Robert Bagratuni confirmed in a May 2026 interview that it will launch before Atomic Heart 2, and he promised more news "soon".

That makes the most common question an easy one to ask and a hard one to answer: when does The CUBE come out? As of November 2026 the honest answer is that nobody outside the studio knows. The Steam page still reads "To be announced", the PC system requirements are listed as TBA, and no beta or playtest has been dated.

What is confirmed is more interesting than a date. The CUBE is an MMO RPG shooter set inside a giant levitating structure whose rows and edges constantly rotate, rearranging the world and the fights inside it. It is coming to PC, PlayStation 5 and Xbox Series X|S, and it is a direct continuation of the Atomic Heart universe. Below we separate the confirmed details from the guesswork, explain what the rotating world could mean for combat, and point out the questions Mundfish still has to answer.

Where the release date stands

The CUBE was revealed at Summer Game Fest on 6 June 2025, when Mundfish showed it alongside Atomic Heart 2. Since then the studio has spent much of its public attention on finishing Atomic Heart: Blood on Crystal, the fourth and final DLC for the original game, which launched on 16 April 2026 and ties the story of the first game into what comes next in the Atomic Universe.

That sequence matters. A studio does not usually say which of two games will come first unless one is noticeably further along, and with the final DLC shipped, the studio's focus has clearly moved to its new projects. Still, an online game needs server testing before launch, and until Mundfish announces a playtest, any release window you see quoted is speculation rather than fact.

A world that turns under your feet

The hook is the structure itself. On the surface the Cube is a geometrically perfect object; inside, it is an anomalous, shifting place full of hostile creatures. Its rows and edges rotate, creating new combinations of environments and new combat situations, and Mundfish warns that the Cube can flip everything in an instant: as the world shifts, so do you. At its core sits an equation capable of altering the laws of reality, and deciphering it is the difference between saving humanity and extinction.

A three-player squad opens fire on a huge armoured machine hiding behind a bulldozer-style shield, a good example of the boss-scale enemies Mundfish promises.

Fans of Atomic Heart will recognise the tone straight away: retro-futuristic Soviet architecture, floating domes, unsettling robots and creatures that feel half-machine, half-organism. If you enjoyed the way Prey mixed retro sci-fi with improvised combat against shape-shifting threats, the atmosphere here is in similar territory, even though the structure is very different.

How an MMO RPG shooter changes the formula

Atomic Heart was a single-player story. The CUBE is built around other people. Steam lists MMO, co-op and PvP features, and the official description promises diverse biomes, quests, powerful bosses, a wide choice of weapons and skills, and "deep and persistent progression" with character development and customisation. One line stands out: even failure will not halt your progression, which hints at a structure designed to keep runs into the Cube rewarding when things go wrong.

Under the hood, Mundfish is using a proprietary Split-Rendering System that it says handles motion in the shifting world, intelligent object tracking and multiplayer synchronisation. That is the technical heart of the project: a rotating world is impressive in a trailer, but keeping it in sync for many players at once is the real test.

A winged enemy swoops in while a tilted block of the Cube, complete with waterfalls and glass domes, hangs above the clouds behind it.

Strengths and open questions

The setting is the obvious strength, and Atomic Heart's success (Mundfish says the first game has passed 10 million players) gives the studio a real audience. Steam lists 13 languages with full audio in English, French, German and Spanish; Polish is not among them at the moment. The concerns are just as clear. Mundfish has never run an online game, business model and pricing have not been announced, and live-service shooters have had a rough few years. Anyone hoping for a story-driven experience should also remember this is not Atomic Heart 2.

Is The CUBE worth waiting for?

If you want to explore the Atomic Heart universe with friends, The CUBE is the project to follow, and wishlisting it on Steam is the simplest way to catch the playtest announcement. Players who mainly loved the solo story are better served by keeping an eye on Atomic Heart 2. In the meantime, The Division 2 offers the kind of co-op loot-and-shoot progression The CUBE is chasing, while Borderlands 3 remains a fun, chaotic RPG shooter to share with a squad, and both are available at sensible prices in the Urazon catalog.