Charater unlockable guide

Choji               Complete chapter 6 
Gaara               Finish chapter 9 
Itachi              Beat kakashi gaiden 
Kakashi             Beat chapter 1 
Kakashi Gaiden      Beat all missions(including S-rank) 
Kankoro             Unlocked from the start 
Kisame              Beat kakashi gaiden 
Might Guy           Beat chapter 8 
Neji                Beat chapter 3 
Rock Lee            Beat chapter 5 
S-rank missions     Beat Story once 
Sakura              Beat chapter 1 
Sasuke              Beat story mode twice 
Shikamaru           Beat chapter 4 


Unlockble missions,story and characters

Hoshigake Kisame(In 2 Player vs. mode): Finish Kakashi Gaiden 
Kakashi Gaiden(Story): Complete all missions(Including S Ranks) 
Sasuke: Pass story mode twice 
Uchiha Itachi(In 2 Player vs. mode): Finish Kakashi Gaiden 
Unlock S Rank Missions: Complete the game once

Restore Chakra
     During  the  Loading  screen if allocated enough time to move the
right  thumbstick enough in a circle. A Blue Chakara Ball will pop-out
and  if you notice your unfilled Stamina / Chakara Bar. It will refill
a  little  about  25%  worth  everytime  you  do this. Between Loading
screens with the Konoha Symbol in the lower right corner.