Disambiguation: For the PS2 game see Maken Shao: Demon Sword.
Demon Sword(不動明王伝,Fudō Myōō Den, "The Legend of Acala") is an action video game developed by TOSE and published by Taito in 1989 for the Nintendo Entertainment System. The caption on the box says to "Release the Power". This is consistent with the game's method of powering up the character's abilities.
How to Play:
Up Down left right use Arrow
Keys A button use A B button use S Rapid A button use Q Rapid B button use W Start Button use Enter Select button use Space bar