Mario, the bad guy? As hard as it may be to believe, Mario is the antagonist in one of Nintendo's early games, working against any and all players who dare to challenge him. In fact, Mario's dark side came out in only his second video game appearance. The game also features Mario's nemesis, Donkey Kong, only now it's Donkey Kong who has been kidnapped and Mario who holds the keys. Players must help the game's new character rescue Donkey Kong. This character also happens to share the game's name: Donkey Kong Junior.
Donkey Kong Junior was developed by Shigeru Miyamoto, mastermind of the original Donkey Kong. Just like those of its predescesor, Junior's levels were built out of four unique screens, with each level featuring larger combinations of screens than the level before, except in Japan where each screen appears at most once per level (also just like in Donkey Kong). Donkey Kong players had no trouble getting to know Junior, and even if the sequel didn't have quite the success of the first game, it still did very well for itself, both in the arcade and later at home.
Mario would next appear in Mario Bros., returning to his old good-guy self. So far he hasn't looked back. For the most part, Donkey Kong has also stayed on the good side of things, though he and Mario still square off once in a while. Actually, he also makes Stanley the bugman's life difficult in the lesser known Donkey Kong 3. Oh well, that's to be expected with big stubborn apes, good or bad!