All songs:
Enter UUDDLRLRBA as a password.

Bonus songs:
Enter one of the following passwords to unlock the corresponding songs.

Bigbeat Mix	REMIX
Euro Beat	GENERATION
Bigbeat Mix, Euro beat	VISUAL
Disco	FEVER
Disco, Bigbeat Mix	SENSE
Disco, Euro Beat	WORLD
Disco, Bigbeat Mix, Euro beat	ALLERGO
Disco, E.N.K.	MOTHER
Disco, E.N.K., Bigbeat mix	PASSION
Disco, E.N.K., Euro beat	NOISY
Disco, E.N.K., Bigbeat Mix, Euro beat	ALTERNA
Disco, E.N.K., Classic 3	RELAXATION
Disco, E.N.K., Classic 3, Bigbeat Mix	SILENT
Disco, E.N.K., Classic 3, Euro beat	MOONLIGHT
Disco, E.N.K., Classic 3, Bigbeat Mix, Euro beat	KOBEBEEF