Alex Kidd in Shinobi World is the sixth, and final, game in the Alex Kidd series, and the second one to be released exclusively outside of Japan.
Alex Kidd in Shinobi World was developed in Japan, where it was thought to have been originally conceived as an Alex Kidd game, unlike Alex Kidd in High-Tech World
which was a sprite swap from another title. However in 2007, articles surfaced which note that the game was originally conceived as Shinobi Kid, a chibi version of Shinobi. The character was later changed to Alex Kidd.
Limited versions of the game were produced in North America, making it a fairly rare title. Like several other Master System games, blue label cartridge versions of the game also exist, which are considered more rare.
The game takes place in a parody world based on Sega's Shinobi franchise where Alex Kidd battles super deformed versions of Shinobi enemies.
In Alex Kidd in Shinobi World, the dark ninja Hanzo escapes 10,000 years of confinement and kidnaps Alex Kidd's new girlfriend. Alex is visited by the ghost of the warrior who originally defeated Hanzo, who explains that his girlfriend will be sacrificed. The spirit lends his power to Alex, who then sets off to Shinobi world in order to defeat Hanzo and save his love.
The game roughly follows the stage design of Shinobi with 4 rounds, each consisting of two stages and a boss stage. Each round is also loosely based on classic Shinobi missions.
The rounds include the city with boss Kabuto, the harbor with a boss based on the Black Turtle attack chopper and Mandara Master, the bamboo garden with boss Robster, and the mansion where Alex battles Hanzo.
In the original prototype of the game, the round 1 boss was a parody of Nintendo Mascot Mario named Mari-Oh (a combination of Mario and the Shinobi villain Ken-Oh). The sprite and name where likely changed to avoid lawsuits, but the boss and his attacks still contain features that make it apparent it was based on Mario.
Alex can move, jump and attack with his sword. The gameplay is considered closer to the original Shinobi than previous Alex Kidd titles. Treasure chests are found throughout the stages which can contain health increases, throwing darts, sword upgrades, extra lives, and a magic ball that will temporarily turn Alex Kidd into an invincible tornado. Alex can also perform a wall-to-wall jump and turn into a flying fireball after spinning around a street post, rope or horizontal bar. Alex starts off each round with three hit points, but can fill out his health gauge to a maximum of six hit points. The player is awarded a "Secret Bonus" if they complete an entire round without getting hit or losing life at any point.