Completing games without getting certain items or by skipping seemingly required portions of gameplay results in sequence breaking, a technique that has developed its own dedicated community. Often, speed of completion and/or minimalist use of items are respectable achievements. This technique has long been used in the "Metroid" game series and has developed into a community devoted to speedruns. NetHack has over time codified many such challenges as "conduct" and acknowledges players who manage to finish characters with unbroken pacifist or vegetarian disciplines, for example. A comparable form of restricted gameplay has been implemented within "World of Warcraft", known as "Iron Man" leveling.