Fun Fact: The only NES game we can think of that allowed players to have sex (well, implied sex, anyway).
Golgo 13 is one of the longest-running manga series in history. Duke Togo, known as Golgo 13, is a professional assassin who has rifle skills that border on the fantastic. Nintendo of America's censorship policies meant that he became a spy instead of an assassin, but many of the mature themes of the manga survived intact in the North American release of this game.
Golgo 13: Top Secret Episode took place in 13 Acts like a season of a television series, and mixed side-scrolling action mechanics, third-person story sequences, and first person “hit” sequences seen through the scope of a high-powered rifle. It was an odd game by American standards, but presaged the day when adult content would make its way into the video game world.