Chess is multiplayer, sudoku/Rubik's is single player. With chess, the game is how well you play against others, and how well you can catch up to the present ga

Chess is multiplayer, sudoku/Rubik's is single player. With chess, the game is how well you play against others, and how well you can catch up to the present game. With single player games a lot of it is about exploration, instead of winning. You set your own win condition.