Constantin Liétard, a Twitter user and computer programmer, found a way to play Pokemon Red with his profile picture.
Those who want to play the game write their next moves (right, down, up, etc.) under this pinned Tweet. With the code entered, the profile picture is updated after 1-2 minutes.
When the posted tweet attracted attention, the user opened a Discord server for both adding new things and for the players to play in a coordinated manner. If you wish, you can also join there and see the progress.