Super Metroid is an 2D, side-scrolling action-adventure game, which primarily takes place on the fictional planet Zebes—a large, open-ended world with areas connected by doors and elevators. The player controls Samus Aran as she searches the planet for a Metroid that was stolen by Ridley, the leader of the Space Pirates. Samus can run, jump, crouch, and fire a weapon in eight directions; she can also perform other actions, such as wall jumping—jumping from one wall to another in rapid succession to reach higher areas. The "Moon Walk" ability, named after the popular dance move of the same name, allows Samus to walk backwards while firing or charging her weapon. The heads-up display shows Samus' health, the supply mode for reserve tanks, icons that represent weapons, and an automap that shows her location and its surroundings. Throughout the course of the game, the player collects power-ups that enhance Samus' armor and weaponry, as well as grant her special abilities, allowing Samus to access areas that were previously inaccessible. The Morph Ball allows Samus to curl into a ball, roll into tight places and plant bombs; the Spring Ball adds an ability to jump while in Morph Ball form. The Speed Booster can be used to run at high speeds, and can crash onto barriers and enemies. The Space Jump allows Samus to jump infinite times to cover great distances, and the Hi-Jump Boots allow for a higher jump. The Grapple Beam can be used to swing across open areas. The X-ray Scope is used to see items and passages through walls and other surfaces. Super Metroid features an inventory screen, in which the player can enable and disable weapons and abilities, combine Samus' weapon beams, or replenish her health by using acquired reserve tanks; when the supply mode is set to "auto", the reserve tanks are automatically be used if Samus' health is depleted. The save system from Metroid II: Return of Samus returns in Super Metroid, which allows the player to save and resume the game at any of the save points scattered around the planet. The player can also save the game at Samus' gunship, which fully recharges her health and ammunition as well. Super Metroid has three endings based on the time taken to complete the game, which determine whether Samus poses with or without her suit. The best ending is achieved when the game is completed under three hours.