Hint: Catch a fish while drifting:
Kara will say that she will not eat fish. When you see a fish jump, hit it with your sword. It will come on board. Eat it, talk to Kara, then she will eat it.

Hint: Become Shadow and use Aura:
Get to the Pyramid (which is right after Dao). When you are in it, you will see a dark space portal. Enter it and become the new character. Talk to Gaia. He will give you Aura. Press B to use Aura. You have to see small stones under the floor.

Hint: Red jewels in diamond mine:
In the diamond mine while you are rescuing the laborers, there is a laborer stuck inside a cleft near the first dark space you encounter. Go all the way up to the left of the dark space and you should see the wind blowing your hair. Use Will's Psycho-Dash to open the wall. He will give you three red jewels as a reward.

Hint: Hidden passage:
In the alley in Euro City is a church-like location. Enter to find a hidden passage containing a surprise.

Hint: Go through Statues in Great Wall of China:
Once you reach the Statues inside a Little Maze, use Freedan and use Dark Friar on the statue. If it did not work, step slightly to the side until you manage to attack it with the Dark Friar. Once the Statue is hit, it will rush through you and you will pass the Statue.

Hint: 360 degree attack:
Hold A and rotate the D-pad clockwise or anti-clockwise. He will attack in all directions.

Hint: Ending bonus:
After completing the game, wait for the credits to end. Kara should be standing next to Will. Wait slightly longer, and Kara will move closer to Will. Wait even more, and you should see Will standing in what looks like a school. After a few lines of dialog, all of Will's friends will start to run by.