Mattel’s MO was to make, slightly inferior perhaps, ports of their Intellivision games and release them on the 2600 to entice people over to the Intellivision. Most of the games Mattel ported were simple shooters that didn’t require much use of the Intellivision’s keypad controller space battle which was renamed space attack on the 2600 is the major exception. Space battle used eleven of the twelve keypad buttons and somehow that all had to be condensed into a single button controller.