50 Greatest Game Design Innovations (excellent article)

From gameplay, to presentation to input devices, videogames are a hotbed of innovation. Ernest Adams notes 50 game design innovations, some that have already made their impact, and others that will shape the future of the medium...

By gameplay I mean the challenges that the game poses to the player, and the actions that the player may take to meet the challenges. The vast majority of these actions are obvious: jumping, steering, fighting, building, trading and so on. But some challenges and actions distinctly advanced the state of the art, and provided new ways for us to play.