A casual game is a video game targeted at a mass market audience, as opposed to a hardcore game, which is targeted at hobbyist gamers. Casual games may exhibit any type of gameplay and genre. They generally involve simpler rules, shorter sessions, and require less learned skill. They don't expect familiarity with a standard set of mechanics, controls, and tropes. Countless casual games have been developed and published, alongside hardcore games, across the history of video games. A concerted effort to capitalize on casual games grew in the 1990s and 2000s, as many developers and publishers branded themselves as casual game companies, publishing games especially for PCs, web browsers, and, after 2007, smartphones. Overview Most casual games have: Fun, simple gameplay that is easy to understand Simple user interface, operated with a mobile phone tap-and-swipe interface or a one-button mouse interface Short sessions, so a game can be played during work breaks, while on public transportation, or while waiting in a queue anywhere Often, familiar visual elements, like playing cards or a Match 3 grid of objects Casual games generally cost less than hardcore games, as part of their strategy to acquire as many players as possible. Any game monetization method can be used, from retail distribution to free-to-play to ad-supported. The term "hyper-casual game" or "instant game" arose in 2017 to describe extremely easy-to-learn games that require no download, being played in an existing app like a web browser or messaging app, and that usually monetize by showing advertisements to the player. History Journalist Chris Kohler wrote in 2010 that Namco's arcade game Pac-Man (1980), which debuted during the golden age of video arcade games, may be the first casual video game, due to its "cute cast of characters and a design sensibility that appealed to wider audiences than the shoot-em-up Space Invaders." It is estimated to have been played more than ten billion times during the 20th century, making it the highest-grossing video game of all time. In 1989, Nintendo's Game Boy was released with Tetris as a free pack-in game. It was quickly learned and immensely popular, and is credited with making Nintendo's fledgling portable gaming system a success. Microsoft's Solitaire (1990), which came free with Microsoft Windows, is widely considered the first hit "casual game" on a computer, with more than 400 million people having played the game . Subsequent versions of Windows included casual games