Alex Kidd in Shinobi World

Alex Kidd in Shinobi World is a side-scrolling action game produced by Sega that was originally released for the Master System in and later re-released for the Wii Virtual Console in. Although developed in Japan, it was released exclusively for the overseas market (North America, Europe and Brazil), with the American version being produced in limited quantities. The game stars Alex Kidd in a parody version of Sega's ninja-themed action game Shinobi, where Alex Kidd fights against caricatures of many of the enemies from Shinobi. It is the final video game to star the Alex Kidd character.

Alex Kidd in Shinobi World's cartridge label is normally the regular red with black grid design, however a much rarer blue label version exists and is considered to be somewhat of a collector's item to Master System game collectors.

Gameplay
Despite being part of the Alex Kidd series, the game mechanics of Shinobi World are different from Alex Kidd in Miracle World and are much closer to the Master System version of Shinobi. Alex Kidd's basic attack is a sword slice, which can be used not only to destroy enemies, but also to open treasure chests. Inside such chests, the player can obtain items such as more health, throwing darts, a powered-up sword, extra lives, and a magic ball that will temporarily turn Alex Kidd into an invincible tornado. The throwing darts and powered-up sword will both replace the Alex's default sword until the player completes the stage or defeats a boss. Other actions that Alex Kidd can perform include a wall-to-wall jump and the ability to turn into a flying fireball after spinning around a street post, a rope or a 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. When the player has full health, all the treasure chests carrying hearts will carry extra lives in their place. When the player defeats a boss with full health, he will gain a "Perfect Bonus" after completing the round. There's also a "Secret Bonus" if the player completes an entire round without getting hit or losing life at any point.

Reception
In an early preview, the August 1990 issue of Computer & Video Games magazine referred to the game as a parody of Shinobi.

Alex Kidd in Shinobi World was critically acclaimed upon release, with an average aggregate score of 85% from Sega Retro, based on eleven reviews. Computer & Video Games magazine gave the game a score of 92% in its September 1990 issue. The reviewer Robert Swan stated that the "game is brill" and a "combination of Alex Kidd in Miracle World and Shinobi" that "works really well." He praised the playability that "becomes progressively more difficult as you go along," and concluded that it is a "great game" overall. In 1991, "The Complete Guide to Sega" issue of Computer and Video Games gave it a 90% score, describing the game as "probably the best in the Alex series so far" and "a hilarious mixture of Alex Kidd and Shinobi." They stated it is "a platform chop-socky game" with "top-notch" graphics and "excellent" sound, including "cutesy version of the Shinobi title music!" They concluded that it is "Dead funny" and "playable as heck," recommending readers to "grab hold of at the first opportunity!"

Sega Pro magazine gave the game a score of 88% in its inaugural November 1991 issue, describing it as a "huge game" with "so much to do that addiction is guaranteed." They stated that it is a "one-player only game but with something this good you wouldn't want anyone else to intrude" and concluded that it is "Great fun." The October 1992 issue of Mean Machines Sega gave it an 88% score, stating that it is the "latest and greatest Kidd game." They described it as "a parody of the Shinobi landscape" and concluded it to be a "a humorous and very playable cart" that is "Recommended."