An arcade game or coin-op game is a coin-operated entertainment machine typically installed in public businesses such as restaurants, bars and amusement arcades. Most arcade games are presented as primarily games of skill and include arcade video games, pinball machines, electro-mechanical games, redemption games or merchandisers. Broadly, arcade games are nearly always considered games of skill, with only some elements of games of chance. Games that are solely games of chance, like slot machines and pachinko, often are categorized legally as gambling devices and, due to restrictions, may not be made available to minors or without appropriate oversight in many jurisdictions. An arcade video game takes player input from its controls, processes it through electrical or computerized components, and displays output to an electronic monitor or similar display. All arcade video games are coin-operated or accept other means of payment, housed in an arcade cabinet, and located in amusement arcades alongside other kinds of arcade games. Until the early 2000s, arcade video games were the largest and most technologically advanced segment of the video game industry. Early prototypical entries Galaxy Game and Computer Space in 1971 established the principle operations for arcade games, and Atari's Pong in 1972 is recognized as the first successful commercial arcade video game. Improvements in computer technology and gameplay design led to a golden age of arcade video games, the exact dates of which are debated but range from the late 1970s to mid-1980s. This golden age includes Space Invaders, Pac-Man, and Donkey Kong. The arcade industry had a resurgence from the early 1990s to mid-2000s, including Street Fighter II, Mortal Kombat, and Dance Dance Revolution, but ultimately declined in the Western world as competing home video game consoles such as the Sony PlayStation and Microsoft Xbox increased in their graphics and gameplay capability and decreased in cost. Nevertheless, Japan, China, and South Korea retain a strong arcade industry in the present day.
As Kei Ikushima reaches the finals of the Sentoki tournament, Ranzou Kihara, who was watching over the tournament, would unleash K-001, a clone created in Kei's image and infused with all of the fight data collected by Orion, upon her. After a grueling battle, Kei was able to defeat the clone and win the match, until Ranzou, not liking the results, decided to restart the match right there and then. As the match got restarted, K-001 proceeded to attack the battered and exhausted Kei in cold blood, delivering vicious blows and strikes, which incapacitated her. She was about to be killed when Shin intervened and fought with the clone. He was eventually able to defeat K-001, but Kei barely survived after all of the injuries she suffered, and was sent to the hospital shortly afterwards. Meanwhile, outside the arena, a mysterious man who goes by the name of "Nixon" watches the entireity of the tournament through some of the TVs displayed on a surplus window. All alone on the streets, Nixon has no memory about his past, living his current life as a vagrant, walking the streets of Tokyo aimlessly and occasionally fighting in underground pit fights as his only livelihood. However, despite his amnesia, he seems to recognize the face of Ranzou Kihara. He dosen't understand it either. He just felt something... oddly familiar about him. It was as if Nixon's mind was drawn to this man, for reasons that aren't clear to himself at all. A rising urge builds up within him: a strong desire to meet Ranzou Kihara himself in order to make sense of his amnesiac mind. Almost a year after the last tournament, Orion would eventually announce the fourth Sentoki: Global Martial Arts tournament. Upon hearing the news, Nixon wasted no time and decided to enter the tournament, his mind dead set on meeting Ranzou, thinking he has all the answers to his past.
