The game's presentation is nicely done. Your sensei speaks to you with calm (if not amusingly clich?) clarity, and the movements of targets and backgrounds are fluid. You are, however, visiting the same locations over and over, so it's easy to get tired of what you see. The controls are sharp for the most part, though the oni sword-fighting, which requires you to block or attack depending on stylus motion, is often non-responsive.
Ninja Reflex is a fun rental. But if you decide to shell out full price for a collection of repetitive mini-games, you need a lesson in spending, my son.