Handheld electronic game by less bright dots). In 1978 the Milton Bradley Company entered the handheld market with Simon, a simple color-and-sound-matching game. Simon had no dedicated display, but featured four colored, lighted buttons; the original version was large enough to be used as a tabletop game or a handheld; later versions became increasingly smaller. The same year, Parker Brothers also released Merlin, a more sophisticated handheld which could play six different games using an array of 11 buttons with integrated LEDs. Despite their relative simplicity, each of these early games was highly successful. The initial success of Mattel and Parker Brothers' entries
The Revenge of Shinobi other than the opening animation (i.e. no plot text or gameplay demos). Using Mijin uses up ninjitsu; in other versions ninjitsu is still available after using Mijin. Mijin also remains selected after it has been used, instead of switching to Ikazuchi. There is also no shouting sound effect when ninjutsu are activated. The final game has 19 music tracks, but this version only has the first seven (the order of music in the sound test is unchanged). Because of this, there are differences in what music is used for what round, but even when the music is in all versions,