Former Unreal evangelist builds his own game engine

In June, Sjoerd De Jong announced his departure from Epic Games, marking the exit of a figure deeply embedded in the world of game engine development. After twelve years serving as a senior director and lead evangelist for the Unreal Engine, De Jong signaled that he was ready for a new challenge, seeking to navigate what he described as a “pivotal point” in the games industry.

His departure was not an exit into uncertainty, but a strategic pivot toward building something entirely new. Instead of simply moving on, De Jong is tackling one of the most pressing questions facing developers today: how to adapt and excel amidst rapid technological change. The answer, it turns out, lies in creating a clean slate.

To pursue this vision, he has embarked on developing his own game engine, which aims to redefine the landscape currently dominated by giants like Unreal and Unity. This new venture is called the Immens Engine, and it is being built alongside a small but formidable team, including former Epic technical director Arjan Brussee.

De Jong’s motivation stems from a deep concern about stagnation. He observed that as established tools grow larger, they accumulate “baggage,” making development cumbersome rather than streamlined. He argued that this added complexity has slowed progress, creating an environment where true innovation is hampered by retrofitting features onto bloated toolsets.

“[Unreal and Unity] get bigger and bigger, [and there’s] more and more baggage that builds over time,” De Jong stated. “So you wonder if there’s got to be something here where we can [have] a clean, modern engine built from the ground up.”

The goal of Immens is explicitly to provide developers with a bespoke toolset designed from day one to accommodate external services, libraries, and tools. This approach seeks to eliminate the need for users to retrofit features onto existing systems, allowing creators to build exactly what they need without unnecessary overhead.

Central to this new philosophy is an acknowledgment of the rise of agentic artificial intelligence. De Jong is integrating this concept into Immens, designing the engine not just as a platform but as a framework friendly to advanced AI architectures. He emphasized that Immens is not simply an “AI engine”; it is a proper game engine that happens to be friendly to AI.

While the broader industry—including Epic Games—is heavily focused on integrating large language models and generative AI tools, De Jong remains grounded in practical development needs. He noted that while these new technologies are exciting, developers still need control over the creative process. He stressed that the future of game creation involves actual development by people, not simply prompting a machine to generate entire games.

By focusing on building an engine that is both powerful and adaptable, Sjoerd De Jong is attempting to carve out a space where developers can focus on creativity, leveraging the power of AI as an external tool within a streamlined, modern foundation. The Immens Engine represents a fresh attempt to solve the industry’s growing need for agility and genuine innovation.