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. Walking past two firebars onto the path collecting coins on the way to come to a gap big enough to jump with a firebar six flames long. Walking on to find a crystal with a 1-up frozen 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,(blue areas have gravity shifting down and reddish-purple areas have gravity shifting up)two black holes, four firebars side by side and another Thwomp. 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 you go clockwise. A Thwomp will try to squash you as you come into a "death zone" with three flamethrowers, a moving platform, and three groups of firebars, each deadlier than the last. And then its off to fight Bowser. On the way he will breath fireball at you, breaking the areas platforms. You will find a life mushroom frozen in crystal. When you get to the top Bowser laughs at you as he swaps the gravity between the two planets. His first attack is a stomp which will make a shockwave move around the planet, 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. Bowser will try to ground pound you again. The player must repeat the attack by only star spining him when he is on his shell a few more times to end the battle.