Use arrow keys to control the snake's movement. Eating food increases your score and snake length. 使用方向键控制蛇的移动，吃到食物可增加分数和蛇的长度。
Game over if you hit the boundary or yourself. 碰到边界或自身会游戏结束。
Press 'S' to start the game. 按 'S' 键开始游戏。
Press Space to pause/resume the game. 按空格键暂停/继续游戏。