Page 2, Naruto: Ultimate Ninja Hints for PlayStation 2
Well I past the game so I should now when your passing the d rank missions like
A tug-of-war on the bridge it says give more than three additional blows to the
Enemy first in the battle trow your opponent and hit the o button fast and there
You have it cool huh
Ok. The bonus characters are Kyuubi Naruto(or demon fox), and cursed seal lv1 saskue. To unlock the saskue, you have to beat all practice, d-rank missions, and I think half of the c-rank misions. To unlock Naruto(Kyuubi), you must complete all b-rank missions!
Now, for the saskue missions, to get all of his chakra down is a NO BRAINER. Just use Neji or Hinata, and use their Level 2 special jutsu, which grants Byhugan, and everytime you hit the opponent, they lose chakra(even when their gaurding!)