Sexual content has been found in video games since the early days of the industry, and games featuring sexual content can be found on most platforms and can be of any video game genre. The inclusion of sex in games has been subject to varying levels of controversy over the decades, sometimes resulting in calls for increased regulation and legislation dealing directly with adult content. In Western gaming, the promise of sexual content in games is commonly used as a marketing tool, but many highly-sexualized games do not feature any explicitly adult content. Though some games do use sex acts or nudity as a narrative device, in-game reward, or a gameplay element, purely pornographic games are uncommon. However, the Japanese pornographic eroge subgenre is popular worldwide. First appearing in the 1980s, these games vary significantly in narrative complexity as well as the level of interactivity, taking forms ranging from the visual novel to virtual reality experiences. History 1980s One of the earliest video games to feature sexual themes was the 1981 text-based Softporn Adventure, published by On-Line Systems for the Apple II. Despite heavy piracy, the game still sold 25,000 copies, roughly equivalent to 25% of the number of Apple IIs sold at the time. In a 1981 article in Time Magazine, On-Line reported that they were making a version of the game for straight women, though this never materialized. Several pornographic games, such as X-Man, were created for the Atari 2600 in the early 1980s. The video game company, Mystique, released three unlicensed games for the Atari 2600; Beat 'Em & Eat 'Em, Custer's Revenge, and Bachelor Party. The games were poorly received (particularly Custer's Revenge, which is considered to be one of the worst games ever made), and Mystique went out of business in 1983. Company Playaround purchased the rights to these games and began distributing them under new titles in 2-in-1 cartridges. In 1983, Entertainment Enterprises, Ltd. released an arcade game called Swinging Singles, which was mostly meant for bars, adult stores, and sex clubs. The game requires the player to drive through the city maze, gathering dots like Pac-Man before reaching a brothel where the player is required to fight off venereal disease and collect keys to unlock sex scenes. Also released in 1983 was Strip Poker: A Sizzling Game of Chance for the Commodore 64 and other 8-bit platforms, which Artworx Software created. In 1986,