Super Mario Galaxy/Fridge

Fridge Brilliance

 * To anyone who may question where the mansion in Ghostly Galaxy came from, the answer does come from thinking about it. The simplest answer is that the Boos found in the level made the mansion like they created Luigi's Mansion.
 * The levels are too small to be galaxies, or maybe you're simply visiting the part of the galaxy that has power stars.
 * If you do two games, one with Mario and one with Luigi, Luigi actually gets more stars than Mario. In the main quest, Luigi finds 3 stars to help Mario, bringing the total stars Mario finds down to 118, not counting all the stars the Toad Brigade found. In Luigi's quest, you play as Luigi and have another Luigi show up, thus bringing the total stars Luigi finds in that game to 121; add that with the total from the last quest, and Luigi's grand star total is 124 to Mario's 118.
 * Cosmic Luigi has the same voice clips as Cosmic Mario. One wonders why... until one realizes that they are controlled by the same Cosmic Comet...