Beat the game once and unlock Rock Lee. Beat the game again with all A ranks and the 3rd Hokage scroll will replace the Kakashi Scroll.
Play Gambunta vs Shukaku mini game
When you are in the level where you are looking for Gaara, get Sakura and Sasuke killed. Then contiue as normal with Naruto. When you beat Gaara in his sand shell you will play the mini game.
Rock Lee
Beat the game once.
Special moves
To do some special moves do these button combinations.
Naruto
up,up,b Uzumaki Barrage
down,down,b sexy jutsu
up,down,b summoning jutsu (note: sometimes fails)
Sauske
up,up,b Lions Barrage
down,down,b Chidori
up,down,b Sharigan
Rock Lee
up,up,b Forward Lotus
down,down,b drop weights
up,down,b Master Lotus