After leaving Epic Games last month, its former ‘Unreal evangelist’ is now building his own game engine

In June, Sjoerd De Jong—an Unreal Engine modder and map creator turned full-time specialist at Epic Games—announced that he was leaving the company after 12 years as its “lead evangelist” for Unreal. In a cryptic departure message, he said the games industry was at a “pivotal point,” and he’s aiming to “work out how to adapt and excel” at addressing the changing needs of videogame development.

We now have a clearer idea of De Jong’s plans for navigating the games industry’s future. In an interview with This Week in Videogames, De Jong revealed what he’s tackling next: He’s building a game engine of his own.

De Jong’s nascent game engine competitor is called the Immens Engine, and he’s building it alongside a small team of co-founders that includes former Epic technical director Arjan Brussee. According to De Jong, he’s intending for Immens to serve as an alternative to the dominance of Unreal and Unity, whose market influence he said has led to a “stagnation” in game development for which challengers like Godot have only just recently started to emerge.

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

Rather than retrofitting features onto a ballooning toolset, De Jong said he hopes Immens can enable devs to create a “more bespoke” toolset of their own, while also being designed from day one to accommodate the “external tools, services, and libraries” that developers rely on.

De Jong said agentic AI is one of the external tools Immens is being built to enable—something he acknowledges is a “hot topic.”

Shortly before De Jong left the company, Epic revealed its focus for Unreal Engine’s future, envisioning a “central role” for “LLMs, generative AI models, and tools like Claude and Codex.” De Jong is skeptical that “those existing engines or existing [development] tools, that were made for humans over the years, are able to really serve [agentic AI].”

While Immens is being built to offer a more accommodating development platform for agentic AI to interface with, De Jong said “it’s not an ‘AI engine'”—it’s a “proper game engine that happens to be friendly to an AI architecture.” Developers, he said, are still going to have to do the developing.

“We don’t want [users to] press a button and generate a game, and then release it alongside the other five million games people have made that way,” he said.