Below is a list of secret wallpapers that cannot be purchased at the fabric store. To get them complete ALL of the missions from a character in the apartment building so that character offers to come over to Kirby's Pad after you complete a stage. Go back and visit Kirby's Pad and the character will be there (just as if they were visiting normally). When the character then makes their standard introduction they will present Kirby with a special wallpaper print. If you miss the character for whatever reason just complete another few stages and the character will once again offer to visit Kirby's Pad.
Unlock Mara Print: Complete ALL of Mara's missions and have Mara visit Kirby's house.
Unlock Zeke Print: Complete ALL of Zeke's missions and have Zeke visit Kirby's house.
Unlock Beadrix Print: Complete ALL of Beadrix's missions and have Beadrix visit Kirby's house.
Unlock Buster Print: Complete ALL of Buster's missions and have Buster visit Kirby's house.
Unlock Carrie Print: Complete ALL of Carrie's missions and have Carrie visit Kirby's house.
During gameplay collect the following various types of music to unlock songs for the sound track. The final three songs 'Dream Land Music', 'Staff Credits Music', and 'Yin-Yarn's Music' become unlocked when you complete the game.