You have to unlock the kitchen observatory. You take mario under the step to get to the kitchen. There should be a life mushroom there. Then run into Rosalina's library. Then go back out. Go back to the place where you found the life. There will be another life there. Back to the library. Back to the life. Ect.


P.S: If it is your first time in the library, you have to listen to Rosalina read a chapter of a storybook to the Lumas.


If you are about to get a game over on a level, then you press pluss on the Wii remote and go back to the observatory and do the infinite life cheat.

Get all 120 Power Stars as Mario and beat Bowser again.After the credits are done you will here Luigi say"Super Luigi Galaxy!".Save and go to the 120 atar file.A new button will appear.it wiil have Mario & Luigi on it.click it and the red part of the file will turn green.then hit play this file and you will be playing as Luigi!Luigi runs faster and jumps higher than Mario,but he always skids to a stop.Get all 120 Power Stars as Luigi and a new galaxy will appear.It is Called the Grand Finale Galaxy-the Star Festival.it takes you back to the Star Festival from the beginning of the game.get all 100 purple coins and star 121 will appear.talk to the mailtoad for a congratulations note on the Wii Message Board.hope I helped:)