The game text is in Spanish, this is a rough translation:

Instructions: In this new adventure you must travel the path of the Biodegradable Masters and defeat them. Show your skills and become
the greatest Ninja Rockstar!
Tip: Combine the keys to perform other moves.
"Z" to kick and "X" to punch

Every bonus stage in between levels: Before continuing practice the strokes with the keyboard. For every two objects destroyed you
gain 1 energy cell. Break them all and you get an extra life!
Bonus Results: Items obtained, Energy gained, Lives earned

Ending: Congratulations! With your help Yumi has managed to defeat the great Masters by consecrating herself as the greatest Ninja Rockstar
of all time! And instead of confronting her best friend, she has decided to stop being a Ninja and return with Ami to play together for
her fans...