I must recognize I really enjoyed this game myself. Most critizisms points to the low difficult, and they may be right, but since the game looks focused on a younger public, I think that's not such a bad thing. The gameplay is accesible and very addictive, the art style is clean, simple and wonderful (couldn't help but thinking about Okami most of times) and the Japanese-stylish music is gorgeous. The plot is quite simple: the Evil Lord has used dark magic to transform animals in evil samurais and builds an army in order to take over the world, and only the main character Hiro (they picked up the name just because it sounds like "Hero"?) and the Mini Ninjas team can stop him.
Anyway, I have plans for coloring this one, but not quite sure of how much time I'll have for that. In the meanwhile, enjoy the lineart.
Lovely pic!