Not sure if this is a bug or not, but every item that is an engine feature cannot be used in games unless you’ve built a custom engine to include this feature. The ONE exception to this rule is the “Rich Backstory” feature. Once this is researched, you can immediately start including it in your games, without adding it to an engine.
While this does make sense in context, as the ability to write a good backstory doesn’t depend on a game engine, the same logic could apply to ‘better dialogues’, yet ‘better dialogues’ requires you to put it into an engine before using it.
Just thought I’d point this out in case this wasn’t intentional.