This iteration as with all Extreme G games is about futuristic racing pilots race plasma powered Tron like bikes in an intergalactic Grand Prix at speeds that are over 999 mph It is possible to break the sound barrier in this game creating a sonic boom While travelling at supersonic speeds all game sounds are muted except the sound of the vehicle travelling If the bike slows down to below supersonic speeds another sonic boom can be heard and all game sounds will resume The emphasis is on speed and creative racetrack design with tracks looping through all three dimensions like roller coasters