I finally finished the game a few days ago. All was worth it. The trouble, the arm cramping. EVERYTHING. Team Ninja delivered a great game for the Nintendo DS and set a standard for other games.
For a game that fully rely on stylus, it was fun. The game was action packed. Being Ryu Hayabusa is not easy. The last boss was annoying. All in all, you feel great once you finished the game. Ninja Gaiden Dragon Sword is a must get for the DS.