Pick your player, choose your board, and get ready to grab some air! Mountainboarding goes underground in this awesome sim that challenges you to ride some of the world?s longest open sewer runs. Score points by pulling sick tricks, race your opponents to the end of the run, or take them down with weapons you collect. Shred your way to mountainboarding fame! Instructions Use your keyboard arrow keys to steer. See in-game help for detailed instructions and other key commands.