Unlock Kakashi Gaiden (Story) Mode: Complete ALL normal and 'S' rank missions.
Unlock 'S' Rank Missions: Complete the game to unlock the 'S' rank missions.
Unlock Hoshigake Kisame and Uchiha Itachi in 2-Player Vs. Mode: Complete Kakashi Gaiden mode to unlock Hoshigake Kisame and Uchiha Itachi in 2-Player Vs. Mode.
Restore Chakra: Rotate the Right analogue-stick quickly in circles when you see a Konoha symbol in the bottom right corner of loading screens. A blue Chakara Ball will appear and refil some of your Chakra gauge if done correctly.