We've seen plenty of canceled, unreleased-but-mostly-finished video games emerge from hibernation onto the Internet over the years: the original EarthBound, Star Fox 2, and Squashed come to mind at first thought. Now we can add Sunsoft's Nintendo Entertainment System game Sunman to the list. Lost Levels has the story of where Sunman came from, where he might have been going, and who he's supposed to be (hint: Man of Steel).
Sunman is a side-scrolling action game that at first glance bears a resemblance to Sunsoft's Batman: Return of the Joker, which was released for the NES in the United States in 1991. Both games feature large, detailed characters and backgrounds that frequently contain multiple layers of parallax scrolling. Any similarity between the two games is skin-deep, however; unlike Sunsoft's obscenely powerful, heavily-armed rendition of Batman in Return of the Joker, Sunman only has his fists to protect himself throughout the majority of his game. It will only take a few minutes' worth of play, however, to figure out that Sunman was intended to be a game that utilized the Superman license. For all of Sunman's mysteries, this observation is perhaps the most readily apparent.
I can see the Superman resemblance when I browse through screenshots of Sunman in action. I'm not convinced we missed anything special when Sunman was quietly dropped from production back in the day, and the game actually makes for a more interesting story now as a lost game because of its mysterious past. Take a look at this game. Do you really think anyone would be clamoring for a Sunman revival for modern consoles today if the original adventure had been released? Or is it only interesting because of the unanswered questions about its origin?