The most popular Engine: Sierra's Creative Interpreter (SCI) games

The Sierra's Creative Interpreter (SCI) engine was a game engine developed by Sierra On-Line, a prominent game developer and publisher in the 1980s and 1990s. SCI was used to create a variety of graphic adventure games, including classics like the King's Quest series, Space Quest series, and Quest for Glory series, among others.

The SCI engine represented a significant advancement in game development technology at the time of its introduction. It allowed for more sophisticated graphics, sound, and user interface elements compared to Sierra's earlier AGI (Adventure Game Interpreter) engine. SCI games typically featured point-and-click interfaces, animated sprites, and sometimes digitized sound effects and speech.