Taiko no Tatsujin DS

There are 6 songs to unlock. In order to unlock them, you need to play the Daily Training Dojo once a day. But you can just cheat your DS clock ahead a day to keep playing the dojo over and over. Keep doing this until you unlock 6 new songs.

Play and pass 20 songs to unlock Oni mode, the hardest mode.

Pass 30 songs to unlock Perfect mode and High-Speed.

In Perfect mode, if you miss one note, you fail the song. To choose Perfect mode after unlocking, go to the Song Select screen and press Down and Right to access the options menu. The bottom of the 2 scrollbars has Perfect mode (which looks like a yellow Don with a gold crown on his head).

With Hi-Speed 4, it is just as it sounds, the notes scroll 4 times as fast. To select it, it is in the same menu as Perfect mode, but it is an animal with his moutn open, and a RED logo next to his name (Green flag is HSx2, Yellow flag is HSx3).