Luigi

Luigi is a main character in the game. You can unlock him and play as him in the galaxies.

Power-Ups
Luigi has the same power-ups as Mario:

Bee Luigi

Cloud Luigi

Fire Luigi

Rainbow Luigi

Boo Luigi

Rock Luigi

Drill Luigi

How to unlock him
To unlock playable Luigi at the galaxies, you need to reach World 3. To unlock playble Luigi on Starship Mario, you need to reach World S.