Quartet 2 [Model 317-0010]

Quartet 2 © 1986 Sun Corp. of America.

Quartet 2 is not a sequel, it's an update available as a conversion kit :
* You can change characters on the fly during the game when you continue, while in the original Quartet, the characters were affixed to the specific color joystick areas.
* You can have just two players at the same time instead of four.