Looking For Name Of A Game

I remember playing this game very very long ago. In the game, I was playing a ninja, and looking at the ninja from bird's eye view. There was many chapters in game, and if I remember right, at each end of the chapter, I had to kill a boss, more powerful monster. There was an old man with a beard, and he was giving me lessons, truths about some ninja stuff, life, etc... After finishing the game once, a better mode would be unlocked. We were a more powerful ninja, and able to kill monsters more easily. And it didn't have magnificent graphics, it was like a cartoon.