The creation of anything that adds to a game "universe" by expanding upon its story.

There were a bunch of Harry Potter displays, taking the old LEGO Harry Potter line and expanding upon it.

The smoke plume of Vesuvius was upright and slender, expanding upon the horizon like a pine tree of white vapor.

She would record the details of these foreign lands for the guild's records, expanding upon the vast knowledge the sages swore to safeguard for civilization.