The degree of influence players have, or feel they have, over a virtual environment. This includes long and short-term influence. A distinction should be drawn between perceived agency and actual agency, as well as between narrative (the potential to alter plot, setting and character) and mechanical (altering the way a game operates).
“Minecraft offers a high level of player agency in part through its breadth of mechanical choice, but also by enforcing no rules and offering only a few vague guidelines.”
“No matter how involved you get, Metal Gear Solid 2 works to undermine and mock any attempt at proper agency.”