-
Step 1
Play the game through normally. Whenever you beat a level, you will be awarded a star. As you progress in the game, more and more galaxies can be unlocked, using the stars you've collected. Even though you only need 60 stars to beat the game, you'll need to collect all 120 stars to unlock Luigi as a playable character.
-
Step 2
Find Princess Rosalina. After collecting the 120 stars to beat the game, go back to the Comet Observatory to talk to her. She will help you arrange a second "final" battle with Bowser that will help you unlock Luigi.
-
Step 3
Request to battle Bowser again. Stick to the spotlights. They have their own gravitational pull so you can stand in the light and move up the wall. You can travel from spotlight to spotlight when two spotlights are touching, but be on the lookout for fire sticks! Follow the spotlights until you reach the progression of platforms that begins with a lava planet.
-
Step 4
Defeat Bowser in the final battle. Bowser will be rolling around in a series of boulders in an attempt to destroy you, so watch out and take advantage of your spin-attack.
-
Step 5
Watch the credits roll and wait for them to finish. When they do, a message will appear on the screen saying that you've unlocked Luigi as a playable character.
