I don't get this game... it doesn't seem like it's possible to lose. I'm on level 21 and I just click left and right of monsters until they die - and while it was fun for an hour or so make little "ka-ping! Fwoosh!" noises in order to facilitate the imagery of a super ninja who was dashing through groups of baddies and leaving geysers of blood behind him, my voice eventually gave out.
Nice chiptune fun and pretty pictures, though.