Short answers, pulled from the story.
Takashi Nishiyama designed the scrolling shooter Moon Patrol while working at Irem. This title featured distant mountains moving slower than foreground rocks to create an illusion of depth called parallax scrolling.
Nishiyama drew inspiration from Wheels on Meals featuring Jackie Chan and Sammo Hung and Game of Death starring Bruce Lee which appeared in theaters in 1972. The resulting arcade game became known as the first beat em up genre prototype.
Nishiyama conceived the original Street Fighter franchise in 1987 with Hiroshi Matsumoto directing the project alongside him. He left Capcom before the sequel Street Fighter II arrived after creating the Hadouken special attack for player characters.
SNK invited Nishiyama to join their company following his departure from Capcom so he could propose using ROM cartridges instead of dedicated arcade boards. These decisions aimed to reduce costs for markets like China and Southeast Asia where piracy made selling dedicated arcade games difficult.
Nishiyama founded Dimps in the year 2000 after leaving SNK. The new company produced titles including Metal Slug and Dragon Ball games while he took on executive producer roles for many projects throughout the early 21st century.