Guerrilla Games co-founder and former Epic Games director Arjan Brussee has announced The Immense Engine, an AI-first game engine built entirely in Europe. The project aims to rival Unreal Engine and Unity with a fundamentally different approach to development.
Arjan Brussee, co-founder of Guerrilla Games and former global director of product management for Unreal Engine, is building a new game engine from the ground up. Called “The Immense Engine,” the project positions itself as a fully European-hosted, AI-native alternative to dominant American and Chinese engines. Brussee shared his plans publicly for the first time in May 2026 on the Dutch technology podcast De Technoloog.
Who Is Arjan Brussee?
Brussee’s credentials span over three decades in the games industry. In the 1990s, he programmed the Jazz Jackrabbit games at Epic MegaGames alongside Cliff Bleszinski. He co-founded Guerrilla Games in 2003 and served as development director across the entire Killzone franchise, before the studio was acquired by Sony. Guerrilla later built the Decima engine, which powers the Horizon series and Hideo Kojima’s Death Stranding.
Between 2018 and 2023, Brussee returned to Epic Games as the global director of product management for Unreal Engine. He also co-founded Boss Key Productions in 2014, which shipped LawBreakers. He left Epic in April 2026 and is now working independently from the Netherlands. Few people in the industry have hands-on experience with both building a proprietary engine from scratch and managing the world’s most widely used commercial engine.
Why Does Europe Need Its Own Game Engine?
Brussee’s core argument centres on digital sovereignty. Most of the dominant engines today are controlled by American or Chinese companies. Unreal Engine is developed by Epic Games in the United States. Unity, although originally founded in Denmark, relocated to San Francisco in 2009. As Brussee told De Technoloog: “No one is currently making an engine that is fully European-hosted, built by Europeans, and complies with European rules and guidelines.”
This is not purely a philosophical position. The EU AI Act begins full enforcement for high-risk AI systems from August 2026, introducing strict requirements around data governance, risk management, and human oversight. A game engine built with European regulatory compliance from day one could appeal not just to game studios but also to defence, logistics, and large-scale 3D simulation projects across the continent. Japanese local governments already use US-built game engines for civil engineering projects; European equivalents may prefer European-hosted tools.
AI as a Core Architecture, Not a Bolt-On
The most ambitious claim behind The Immense Engine is its AI-first design philosophy. Brussee argues that existing engines like Unreal were “made for and by people who have to click through a menu with a mouse,” and that retrofitting AI into these decades-old architectures will always be limited. The Immense Engine would instead treat AI agents as a fundamental building block.
“If you are smart and know how to put a good framework of AI agents to work, you can do the work of ten or fifteen people,” Brussee stated. AI agents like Claude and ChatGPT are intended to function as modules within the engine, with new LLM capabilities easily integrated. The vision is that small teams could achieve production output previously reserved for much larger studios, a prospect especially attractive to indie developers operating on tight budgets.
The Current State of the Game Engine Market
The global game engine market was valued at USD 1.5 billion in 2025 and is projected to reach USD 1.6 billion in 2026, growing at a CAGR of 6.8% through 2035 according to Global Market Insights. Unity Technologies led with approximately 41.2% market share in 2025. The top five players (Unity, Epic Games, Cocos, YoYo Games, and Construct) collectively held 68.4% of the market.
Unreal Engine 5 remains the gold standard for AAA-quality 3D rendering, powered by technologies like Nanite and Lumen. Its licensing model charges a 5% royalty on gross revenue exceeding USD 1 million per product. For non-gaming commercial use, Epic offers a seat-based subscription at USD 1,850 per year. Unity operates on a freemium model: Unity Personal is free for teams under USD 200,000 in annual revenue, with Pro and Enterprise tiers requiring paid subscriptions.
The Unity Pricing Crisis and the Trust Gap
The timing of The Immense Engine announcement is not accidental. In September 2023, Unity announced a “Runtime Fee” that would charge developers per game install, a move that triggered an industry-wide backlash. Studios publicly protested, and some threatened to switch engines entirely. Unity reversed course in 2024, scrapping the runtime fee and replacing it with higher subscription prices, but the damage to developer trust was substantial. Unity’s share price dropped more than 50% from its highs, and hundreds of employees were laid off.
The fallout directly benefited open-source alternatives. Godot, an MIT-licensed engine, saw a 400% increase in GitHub stars between 2022 and 2024. Godot excels in 2D development and lightweight projects, is completely free with no royalties or licensing surprises, and has a roughly 40 MB editor. However, it still lacks the AAA 3D rendering capabilities, mature multiplayer frameworks, and massive asset ecosystems that Unreal and Unity offer. The Immense Engine appears to be targeting the gap between Godot’s accessibility and Unreal’s power.
What About Existing European Engines?
Europe is not without game engine heritage. Germany-based Crytek developed CryEngine, which gained fame through the Far Cry and Crysis series and has been available for free with a 5% revenue share since 2018. However, CryEngine has struggled with adoption due to its narrow focus on first-person shooters and complex licensing history.
Closer to Brussee’s own background, Guerrilla Games’ Decima engine has powered critically acclaimed titles including the Horizon series and Death Stranding. There are unconfirmed reports that Sony is considering licensing Decima to third-party developers, though nothing has been officially announced. The Decima engine is proprietary to Sony, which limits its availability. Brussee’s first-hand involvement in building Decima makes his new project particularly interesting: he is essentially trying to create something broader and more open than what he helped build before.
Limitations and Open Questions
Despite the credibility of its founder, The Immense Engine is very much in its infancy. No technical architecture, licensing model, release date, team size, or funding amount has been disclosed. There is no public demo, no development roadmap, and no confirmed beta access. The project currently exists as a stated vision with no verifiable deliverables.
The “fully European” framing also has caveats. Sources familiar with the project note that the AI agent stack currently relies on US-based providers, including OpenAI and Anthropic. Brussee has mentioned Mistral, a French AI company, as a possible European LLM alternative, but no integration has been confirmed. Building a genuinely sovereign European engine while depending on American AI infrastructure presents an obvious tension.
Community reaction has been mixed. Some developers on forums like Tom’s Hardware have expressed enthusiasm about a less bloated alternative to Unreal, while others have raised concerns about the long-term maintainability of AI-generated codebases and the potential for “technical debt no one quite understands.”
What This Means for Developers and the Wider Industry
If The Immense Engine delivers on even part of its ambition, the implications are significant. An AI-native engine that genuinely enables smaller teams to match larger studios’ output would lower the barrier to entry for game development globally. Combined with European hosting and regulatory compliance, it could open new markets in government simulation, defence visualisation, and industrial 3D applications.
However, the history of game engines shows that technical innovation alone is not enough. CryEngine was arguably ahead of its competitors graphically for years but never achieved mass adoption. Success requires a developer community, documentation, tooling, platform support, asset pipelines, and long-term financial sustainability. Unreal Engine’s ecosystem has been built over decades; Unity’s developer base numbers in the millions. Any new entrant faces enormous network effects to overcome.
Key Questions Developers Are Asking
When will The Immense Engine be available?
No release date, beta timeline, or technical roadmap has been shared. The project appears to be in early development as of May 2026.
Is this engine only for game development?
No. Brussee has explicitly stated that The Immense Engine is designed for use beyond gaming, including defence, logistics, and large-scale 3D simulation. Real-time 3D world creation is increasingly relevant across multiple industries.
What will the licensing model look like?
Unknown. For reference, Unreal charges a 5% royalty above USD 1 million in revenue, Godot is completely free under the MIT licence, and Unity uses a tiered subscription model. The Immense Engine’s pricing has not been announced.
How will AI integration actually work in practice?
Brussee describes AI agents as modular components within the engine, with easy integration of new LLM features. However, no technical demonstrations or architecture details have been published.
Can a new engine realistically compete with Unreal and Unity?
The barriers are high, but not impossible to overcome. Godot’s rapid growth since 2023 proves there is appetite for alternatives. The Unity pricing controversy showed that developers will reconsider platform loyalty when trust is broken. If The Immense Engine can deliver a credible product with a clear value proposition, it has a window of opportunity.
The Verdict: Credible Vision, Unproven Execution
The Immense Engine has one of the most experienced founders imaginable behind it. Arjan Brussee has built engines, shipped major franchises, and managed the product strategy for the world’s most popular commercial engine. His argument that today’s engines were not designed for AI-first workflows is difficult to dismiss. The European sovereignty angle adds a practical regulatory dimension that goes beyond marketing.
But a vision is not a product. Until there is a demo, a technical specification, or a confirmed studio partnership, The Immense Engine remains a compelling pitch rather than a proven alternative. The game development community will be watching closely as more details emerge. For those interested in how engine technology shapes the games we play, developments like DLSS 4.5 and its impact on modern game engines offer useful context for what is at stake.
