Released in 1995, this is one of the more innovative Sonic games. It features the 'bungee' rings, which allow 2 characters to gain incredible speed or even fly by using each other for momentum. Instead of playing the zones in a predetermined order, you select the zone to play next (as well as your partner for the next level) from an area called the World Entrance. Another unique feature is the changing of levels according to the time of day. Chaotix also introduced Vector, Espio, Charmy, Heavy, and Bomb, and re-introduced Mighty, not seen since SegaSonic the Hedgehog.
Note: Each musical piece in the game has its own title in the Sound Test.