[2] Ninja-kun's Demon Castle Adventure features three upward scrolling levels that repeat and become more difficult.

In Japan, Game Machine listed Ninja-Kid on their November 15, 1984 issue as being the second most-successful table arcade unit of the month.

[3] After Jaleco had ported the game and its sequel to the Famicom and MSX in Japan, the company created Ninja-kun's younger brother, Ninja JaJaMaru-kun and created their own series titled Ninja JaJaMaru-kun.

Game Machine listed Ninja-Kid II on their June 1, 1987 issue as being the tenth most-successful table arcade unit of the month.

[4] The Famicom version was going to be released in North America by Sammy as Ninja Taro (not to be confused with the Game Boy game Sengoku Ninja-kun, which was released in America as Ninja Taro), but the American version was cancelled.