so-so
It was a nice concept, but a few things really ruined it for me.
1 - I know the others have said this, but it seems the most important - the master's instructions, which are sometimes important scroll extremely slowly and there is no way to load them - you can only skip them altogether...
2 - stealth is not much use, it is better to just run away, it is rarely possible to get past them without get close enough that they will detect you
3 - you really should start with ninja stars or else have a block. Even killing the easy ninjas at the beginning takes ages to do without getting hit by their stars...
4 - jump is really weird, you can't change on the up, but can on the way down? change it to either can change or can't, it is very counter-intuitive.