Bugged, choppy control, basic design, no save
The graphics and sound were quality, but that's about the only upside.
A ninja has dexterity, controls should be smooth and fluid. Combos should flow like water. In this, you can only continue a strike after your last action is completely finished. This hinders air combos and makes things like jumping to dodge a hassle because you must wait for the landing animation to completely finish before you can attack again.
Even basic scrolling levels would be nice, rather than a solitary platform with stuff on it.
Saving is a must, or if you keep the codes at least make it so that the code contains your upgrade info as well.
Code the boss fight to end even if the boss has negative health. I overkilled him with an air combo and when he disappeared the level didn't end, and the little -210 part of his health bar sat there mocking me. Also, since you can't restart the level from the pause screen, i was forced to go back to the main menu, which erases all your progress. That is simply poor design, and should be fixed.
Among other issues are overpowered weapons, the Force Orb especially is simply "Go to corner, click until level ends, repeat." It would also be nice if projectiles aimed at your mouse instead of following preset paths.