Keaton's acting evolved from classical face emoting - as done in pantomime, theater, variety musicals, comedy acts and early silent movies - to his own style of the stone face, emotionless simpleton, who physically interacted with his surroundings using his acrobatic stunts. It was a linear evolution. The newer generations are more familiar with his more popular personal style of acting, used only as a credited character, not when doing uncredited bit parts.