Room State

In almost all Metroid Games, Room States are what determines what is in a room at what time. Most rooms have only one room state, but many have two, three, or even four room states. Different room states are triggered by certain events occurring within the game. This can range from collecting an item to beating a boss. Room States determine which areas are accessible at what times, and change throughout the game. Some of the changes are aesthetic, such as the rain ceasing to fall in the open area of Crateria after the acquisition of Power Bombs, while some are very important, such as the destruction of Sector 5 after acquiring the Plasma Beam. Changes in Room States are generally irreversible, but are usually for the better, with one of few exceptions being Dark Pirate Commandos appearing in Torvus Bog after the acquisition of the Grapple Beam.