Ninja Spirit is an arcade game with currently limited available information. The exact developer, release year, and detailed gameplay are not readily known.  Given the title, a classic side-scrolling action beat 'em up with ninja themes seems probable, involving a ninja character battling various enemies across multiple levels.  The game likely featured iconic elements such as shurikens, swords, and other ninja weaponry.  Further research into arcade game archives is needed to obtain complete information about its development history.

Ninja Spirit

Ninja Princess (64k Ver. not encrypted)