Underground is very dangerous because there are little light and oxygen. Red ball and blue ball in underground in this adventure game, game same fireboy and watergirl games. Because logic is the same in this game red ball and blue ball cooperate, we remember in fireboy and watergirl games they cooperate too. Arrow keys to move red and blue balls space bar to jump, enter button to change ball careful for this. Cooperate eachother and pass all levels. Good games.
Red Ball and Blue Ball Underground