I'm going to clue you in on two of the most popular game engines that people use in the industry, Unity and Unreal Engine.

Unity—a popular cross-platform game engine that powers titles like Hollow Knight and Pokémon Go— announced that a new Runtime Fee would take effect on January 1, 2024.

Unity Technologies, headquartered in San Francisco, might be best-known for its cross-platform game engine Unity. For over a decade, Unity has been a go-to toolset for video game production ...

Popular game engine Unity announced a “Runtime Fee” policy on Sept. 12 that, starting Jan. 1, would incur a fee upon developers each time a game utilizing Unity was downloaded.

That would seem to disallow the kind of "Unity Runtime fees" the company soon plans to charge for Unity game installs—at least for old, un-updated projects that decide to stick with the old ToS.