In late July 2026, former Epic Games "Unreal evangelist" Sjoerd De Jong revealed he is building Immens Engine—a from-scratch game engine meant to challenge the accumulated complexity of Unreal and Unity. De Jong, who spent 27 years with Unreal Engine and 12 at Epic, has teamed up with Guerrilla Games co-founder and ex-Epic technical director Arjan Brussee to create an alternative that treats AI agents, external services, and bespoke studio workflows as foundational design principles rather than afterthoughts.
A New Engine Builder Enters the Arena
On July 27, PC Gamer reported that Immens Engine is under development with a small team of co-founders. The project emerged after De Jong left Epic in June, describing the games industry as being at a "pivotal point." His departure notice struck a cryptic tone, promising to "work out how to adapt and excel" at meeting new development challenges. The Immens announcement supplies the missing context.
De Jong is critical of how dominant engines have evolved. "[Unreal and Unity] get bigger and bigger, [and there's] more and more baggage that builds over time," he told This Week in Videogames. That, he argues, has contributed to stagnation, with challengers like Godot only recently gaining traction. Immens is his answer: "a clean, modern engine built from the ground up."
Why De Jong and Brussee’s Background Matters
The names behind Immens carry real weight. De Jong was a senior director and lead evangelist at Epic, meaning his job was helping studios adopt Unreal Engine at scale. Brussee co-founded Guerrilla Games (makers of the Horizon series), worked on Epic’s Jazz Jackrabbit titles, and later returned to Epic as a product management director for Unreal Engine. Together, they combine deep engine-architecture knowledge with first-hand experience of production pain points.
Brussee had already been public about his desire to build a European-hosted alternative to major American and Chinese engine platforms—one that aligns with European data and compliance rules, and could serve sectors like defense and logistics alongside games. Immens is the vehicle for that vision.
What Immens Engine Promises for Game Developers
The central proposition is not a stripped-down “indie” engine, but a platform that lets developers assemble a more bespoke toolset. De Jong envisions an engine designed from day one to integrate external tools, services, and libraries, rather than bolting them on later. A studio could plug in proprietary procedural-generation systems, custom build infrastructure, or domain-specific simulation libraries as easily as they might add a plug-in today.
For Windows PC developers, this could translate to fewer friction points when adopting custom pipelines. Instead of fighting a monolithic editor’s assumptions, teams might tailor the environment to their exact needs—potentially improving performance profiling, asset management, and platform-specific optimizations early in development.
AI-Friendly, Not an AI Engine: What That Really Means
Agentic AI is a core part of the design, but De Jong pushes back hard against labeling Immens an “AI engine.” His goal is “a proper game engine that happens to be friendly to an AI architecture.” Developers will still do the developing; he explicitly rejects the idea of “press a button and generate a game.”
The distinction matters because current engines were built for humans clicking through menus, and retrofitting them to support autonomous AI agents risks deep architectural compromises. Brussee has argued that making AI agents first-class citizens could let small teams accomplish substantially more—by automating tedious, repetitive tasks like shader profiling, dependency tracking, crash reproduction, or test-case generation across GPU configurations.
Immens is betting that by designing for agentic workflows upfront, it can offer a safer, more auditable integration than rivals can via patches and add-ons.
For Windows PC Gamers: Potential Upsides and Long-Term Hopes
Game engines directly influence the performance profiles of PC releases—shader stutter, ultrawide support, frame pacing, and GPU scalability all depend on engine defaults and tooling. If Immens enables bespoke pipelines with better profiling and earlier optimization, it could raise the quality bar for Windows titles from studios that adopt it.
Modding could also benefit. A clean-slate engine built with interoperability in mind might offer more standardized ways to inject custom content, provided the design doesn’t lock everything behind proprietary services.
But these are long-term potential benefits. No public build exists, and Immens will need years of iteration on real projects before it can compete with Unreal’s decades of production validation.
The European Angle and Non-Gaming Use Cases
Brussee’s emphasis on a European-hosted engine is more than branding. Organizations with data-residency, procurement, or sovereignty requirements (defense, industrial simulation, digital twins) may prefer a locally governed alternative. Immens could thus address a market beyond entertainment, where compliance is a genuine differentiator.
Still, technical capability will decide adoption. Studios and enterprises will demand robust content import, asset cooking, debugging, profiling, and platform support before they commit.
Where Unreal Engine 6 Fits In
The timing is impossible to ignore. Epic announced Unreal Engine 6 on June 17, one day before De Jong’s departure. UE6 embraces agentic AI openly—planning deep integration with LLMs, generative models, and open APIs via the Model Context Protocol. Epic’s roadmap envisions a gradual migration path from UE5, carrying forward a massive ecosystem.
Immens, by contrast, has no legacy to protect. It can make more radical assumptions about automation and interfaces. The risk is that it also lacks Unreal’s maturity, documentation, talent pool, and production track record. This is the classic startup-versus-incumbent trade-off.
What Should Developers and PC Users Do Now?
For game developers: No immediate action is needed. Immens is still early-stage, with no public build, licensing model, console support, or shipping timeline. Teams in pre-production on new titles might watch its progress, but existing projects should stick with proven engines. Studios dissatisfied with current tools could add Immens to their radar for future evaluation.
For enterprise IT and simulation teams: If European hosting and compliance align with your procurement rules, monitor Brussee’s public statements for early-access opportunities.
For PC gamers: Don’t expect any Immens-powered games soon. But the engine’s emergence is a healthy sign that the market may become more competitive—and competition eventually leads to better-performing games.
The Road Ahead for Immens Engine
Immens Engine is less a product today than a statement of intent. Its founders’ experience gives it credibility that most engine startups lack, but the hardest challenges—building a full toolchain, winning developer trust, and sustaining years of iteration—are still ahead.
If De Jong and Brussee can deliver a genuinely clean, composable platform that makes AI assistance predictable and safe, Immens could influence the industry even before it ships a single blockbuster game. For now, it stands as the most concrete example yet that veteran engine architects believe there is room for a fundamentally different approach—and that the moment to build it is now.