Way of extending potentially short gameplay almost but not quite infinitely by setting completed tasks (such as collecting a certain number of items and doing optional sidequests) as a percentage, sometimes given explicitly. This feeds into the obsessive nature of the player. Gamer opinion regarding this mechanic is roughly divided between those who feel that the goal should be easy for all players to obtain and those who believe it must be difficult enough for only a few players to reach it during the game's lifetime. It is always Serious Business, however. See also True Final Boss.