The Fate of the Universe

The Fate of the Universe is the only mission of Bowser's Galaxy Reactor, and is the final mission of Super Mario Galaxy. The mission's objective is to defeat Bowser and collect the last Grand Star.

Layout
The player begins on a planet with stone walls and spotlights that determine the direction of gravity; jumping into a spotlight will have Mario stand on the wall. The player must cross the walls using the spotlight while avoiding Dry Bones and Fire Bars to reach a vortex that will bring the player to a lava filled planet with many sinking and moving platforms. After dodging fireballs on a rotating lava rock, the vortex at the end will take the player to an ice planet. As the player moves along, ice platforms will form in front of them, creating a path. The vortex at the end of the ice planet will take the player to a sand planet where the player has to dodge tall Fire Bars on moving platforms to reach the vortex at the end. Next is a two-dimensional platforming challenge with blocks appearing as the player progresses; however, the platforms will disappear after a short time. The player must Wall Jump and avoid Fire Bars while also navigating a gravity chamber at the end to reach the next vortex. The final vortex will take the player to a large, round lava chamber with many Thwomps, Bullet Bills, and Banzai Bills, as well as sinking and moving platforms. The Launch Star at the end will send the player to a stairway where a cutscene with Bowser and Bowser Jr. will begin. As the player makes their way up the stairs, Bowser Jr. will send out meteors to destroy the path behind them. Reaching Bowser will begin a dialogue, followed by the final battle.

Bowser Battle, Phase 1
The first phase of the final battle takes place on a stone planet. Bowser will attack by sending out shockwaves and by curling into a boulder and rolling at the player. To damage Bowser, the player needs to spin at Bowser's head when he's in a boulder, similar to how the player would defeat a regular boulder. Attacking Bowser will cause him to start spinning along the planet, and spinning into Bowser again will damage him. After Bowser is damaged the first time, his attacks will get faster during the second attack, and Bowser will spin around the planet twice after knocking him out of the boulder. Damaging Bowser once more will begin the second phase of the fight.

Bowser Battle, Phase 2
The next phase takes place on another planet, which Bowser and Mario will be sent too after completing the first phase. Bowser will attack by sending out fireballs and by curling up into a ball and attempting to roll over the player. When Bowser is in this state, the player needs to spin into a Stretch Plant to knock it at Bowser, which will send him spinning across the planet, and the player must damage him similarly to the last phase. Doing this twice will send Bowser and the player to the next planet. Alternatively, the player can knock the Stretch Plants into Bowser as he is shooting fireballs.

Bowser Battle, Phase 3
The third phase is similar to the previous battles with Bowser. Bowser will attack by sending out several shockwaves, firing fireballs, or by curling up into a Spike Ball and attempt to roll over the player. After Bowser is done rolling, he will jump up and try to land on the player. If the player is positioned over a blue orb, Bowser will shatter it upon landing, burning his tail and will begin running around the planet. Spinning into Bowser's tail will send him spinning around the planet, and spinning into him again will damage him. Repeating the process and damaging Bowser a second time will defeat him, and reward the player with the final Grand Star.

Enemies

 * Dry Bones
 * Fire Bars
 * Galactic Tornadoes
 * Bullet Bills
 * Banzai Bills
 * Thwomps
 * Bowser (boss)

Planets visited

 * Starting Area
 * Lava Planet
 * Ice Planet
 * Sand Planet
 * Lava and Water Planets
 * Space Junk Area
 * Lava Tower Planet
 * Stairway
 * Bowser's Rock Planet
 * Bowser's Shell Planet
 * Galaxy Reactor