Ninja Gaiden, released in Japan as Ninja Ry?kenden and as Shadow Warriors in Europe, is a hack-and-slash platform game. Tecmo developed and published it for the Nintendo Entertainment System (NES). Its development and release coincided with the beat ’em up arcade version of the same name. It was released in December 1988 in Japan, in March 1989 in North America, and in August 1991 in Europe. It has been ported to several other platforms, including the PC Engine, the Super NES, and mobile phones. Gameplay: Ninja Gaiden is a side-scrolling platform game in which the player takes control of the player character, Ryu Hayabusa, and guides him through six “Acts” that comprise 20 levels. A life meter represents Ryu’s physical strength, which decreases when he is hit by an enemy or projectile. A “life” is lost when the life meter is depleted entirely, when Ryu falls off the screen, or when the timer runs out. A game over screen appears when all lives are lost; however, the player may restart the level where this occurred by continuing. At the end of every Act, the player fights a boss; bosses have life meters depleted by player attacks. When its life meter is depleted entirely, a boss is defeated. Each boss is one of the “Malice Four”—evil underlings of the Jaquio, the game’s main antagonist. The Malice Four consist of Barbarian, Bomberhead, Basaquer, and their leader Bloody Malth.