NovaLogic · Philips CD-i · 1993 · Cancelled at pre-alpha — prototypes leaked
A genuine Super Mario World sequel, built for the Philips CD-i by an American studio, which Nintendo actually approved of — before the CD-i's collapsing sales killed it at roughly 80% complete art and 30% code.
Super Mario's Wacky Worlds is the great what-if of the CD-i era. Developed by NovaLogic — later famous for the Delta Force military shooters — it was conceived as a genuine sequel to Super Mario World, the 1990 Super NES masterpiece, and built for Philips's ill-fated CD-i platform under the licensing arrangement that also produced the notorious Zelda CD-i games. Unlike those titles, which are remembered as embarrassments, Wacky Worlds was taken seriously and reportedly received positive feedback from Nintendo when an early prototype was shown. The game was a side-scrolling Mario platformer built along Super Mario World's lines, with worlds themed around real locations on Earth, and the surviving builds suggest a competent, faithful entry rather than the shovelware the CD-i is now synonymous with. Development began in 1992 and ran until June 1993, and the game got substantially further than most cancelled projects. The final prototype is a pre-alpha, version 0.11, completed on 3 March 1993 after roughly a year of work, and the project had reached approximately 80 percent of its art, 95 percent of its design, and around 30 percent of its code. The unfinished code is what damns it: a game with nearly all its assets and almost none of its engine. What killed it was not quality but the platform. The CD-i's sales were collapsing, and there was no commercial logic in finishing a Mario game for a machine nobody was buying. Development was halted, and three prototypes have since entered circulation among collectors; one sold on eBay for $1,000, and a build has been leaked in ISO form and can be played on emulators or burned to a disc for real CD-i hardware. It stands as a poignant curiosity: the last officially sanctioned Mario platformer Nintendo never made, stranded on the worst console ever to carry its characters.