>The original meaning of "game engine" which made much more sense was: "the actual code which enables the game to run", e.g. just the runtime parts, the tiny pi

>The original meaning of "game engine" which made much more sense was: "the actual code which enables the game to run", e.g. just the runtime parts, the tiny piece of code that's dangling off the end of the asset pipeline ("tiny" relative to the work that needs to go into authoring tools and asset pipeline). It still means that. When you hit the "Build" button in the Unreal IDE, you get your assets and custom code packaged together with the engine code. It doesn't bundle the IDE. I haven't used Unity in years, but from what I remember it works the same. The IDE is only there (at least in Unreal's case) to give artists and programmers an easy workflow to develop the finished product, after which it's cast adrift. You need an integrated IDE these days because the number of features that are included in the engine is insane. If you're doing shaders and you're not writing them in raw GLSL, then the Unreal materials interface in the IDE is indispensable. If you're doing visual scripting (eg. Blueprint) the same applies.