If the game freezes, just click inside it (games can get unresponsive if you click elsewhere on the page).
You are Rascal Ninja, a nice guy who just wants to learn all ninja doctrines of the world by just stealing their scrolls! Run, jump and climb through 100 levels and try to not kill anybody on your journey, or better yet, try to not be detected! Use your shurikens to grab scrolls far away from you and fool your enemies with your shadow copy technique!
A/D or Arrows: Move
A/D or Arrows Twice: Run
S or Down Arrow while Running: Slide
L or Left Ctrl: Jump
K or Space (+ direction): Shuriken
S or Down Arrow (press for 2s): Shadow Copy
W or Up Arrow (press for 2s): Invisibility
ESC: Stage Select / Title Screen / Menu
You can also double jump, wall jump and hide behind bushes and fog or underwater. And your shurikens can grab scrolls far away and bring them to you.