Successfully complete the indicated task to unlock the corresponding character in Free Play mode:
- Birdo: Defeat Birdo in Luigi's stage 1.
- Donkey Kong: Defeat Donkey Kong in Plob's stage 1.
- Dragon Lord: Defeat Dragon Lord in stage 9.
- Koopa: Defeat Koopa in final stage.
- Luigi: Defeat Luigi in Yoshi's stage.
- Plob: Defeat Plob in Slime's stage.
- Waluigi: Defeat Waluigi in Wario's stage 2.
- Wario: Defeat Wario in Luigi's stage 2.
Successfully complete all stages to unlock the "BGM" option in the "Collection" menu.