In this guide you will see how to unlock all the minigames and songs instantly.
Go to the main menu options screen.
Go to the credits.
Go to this screen (5/32) and press, you will get back to the menu where the "M" was, repeat this step 3 more times.
In the 4th time you perform the previous step, a padlock will appear instead of the heart, press it and you will have unlocked all the minigames and music.