In 1981, Endō joined Namco. During his time with the company, in 1982 he created the wildly popular shoot 'em up game Xevious, single-handedly designing, programming and drawing the graphics for the game. Later he produced The Tower of Druaga and Grobda, both released in 1984. Xevious set the template for vertical scrolling shooters, while The Tower of Druaga laid the foundations for action role-playing games.
Furthermore, he entered the mobile phone game market at an early stage, creating titles such as Sangokushi Nendaiki, Kētai Shachō, Unō Paradise, Beach Volley Girl Shizuku among others.