Bowser's Star Reactor

Bowser's Star Reactor is a level located in Super Mario Galaxy and the first level where Mario fights Bowser. Before Mario fights Bowser, he has to travel through a short level that resembles one of the Bowser levels from Super Mario 64 (the music is also the same from those levels).

After Mario passes, Bowser will come down at start breathing fireballs at the platforms that Mario is on. This causes the platforms to start breaking and Mairo then has to go from platform to platform before they break. After a while he reaches the stage where Bowser is on. Bowser laughs and the gravity of the planet above them pulls them up.

Mario fights Bowser on this planet and after he defeats Bowser, the king of the Koopas mentions that he is not defeated yet. Bowser then uses some sort of magic to disappear. Bowser leaves a Grand Star behind, which Mario gets.

The Fiery Stronghold
Mario starts the level flying through space past Bowser's airship fleet and landing on a platform with a long path bending upwards and a giant warp pipe attached to it. The player will have to walk on the path. The player will have to walk on to find a crystal with a 1-Up Mushroom in it and the main platform with two firebars, a flamethrower and a Thwomp. Up next is a green platform which rotates 180o to come to a platform with shifting gravity. The player will have to go onto a yellow platform to come to a grey platform with four firebars in a cross shape turning counterclockwise and a 1-Up Mushroom if the player went clockwise. A Thwomp will try to squash Mario as the player came into an area with three flamethrowers, a moving platform, and three groups of firebars. After passing through theese obstacles, the player will have to to fight Bowser. On the way he will breath fire at Mario, breaking the areas platforms. The player can obtain a Life Mushroom trapped in a crystal. When Mario gets to the top Bowser laughs at the player as he swaps the gravity between the two planets. His first attack is a stomp which will make a shockwave move around the planet and Mario will have to jump over it. Then Bowser will try to ground pound the player. The player should stand on a blue disc just before he attacks and Bowser will set his tail on fire when he ground pounds. He will run around the planet, and the player must try and Star Spin to attack his tail that will send him spinning on his shell. The player should Star Spin at him again to give damage. He will then shoot fireballs at Mario. The player will have to repeat this process to defeat Bowser.