Deep Dark Galaxy
Deep Dark Galaxy is a ghost-type galaxy in Super Mario Galaxy, like the Boo's Boneyard Galaxy and the Ghostly Galaxy. The main planet in it has a beach with many Toads and Crabs. There are also Magikoopas near it. The thing that makes it "spooky" is that there is an underwater cavern (it's rather deep and dark, giving the Galaxy its name) filled with ghost ships. There are very few planets aside from the big, main one. Guppy makes his second appearance here.
This is the main planet of the galaxy. It has a small beach with a few Crabbers, one Starbag and, in the water, a chest with a 1-Up Mushroom. The Toad Brigade often stop here and have installed a cannon, two lawn chairs and an umbrella. In the mission Bubble Blastoff, the cannon is under control by a water Undergrunt Gunner, which must be defeated to gain access to the cannon. Other features include several palm trees and a few coconuts. On the other side of the planet there is a cave with many strange machines situated around an underground lake. The lake takes up much of the planet and is very deep. At the bottom there is a wrecked ship and two rocks shaped like stars. There is a variety of sea life in the lake, including Bloopers, Gringills, Preying Mantas, Urchins, Mines and a Jellyfish. There is a passageway in the lake that surfaces into a cave, where there is a ghost ship inhabited by several Boos. Kamella is fought on this ship twice. If Mario manages to catch crabs, he might get a 1-UP.
This is a small planet with many Octoguys living on it. It has a Sling Star on the top and a Fire Flower on the bottom. There is a Rainbow Star right in front of the planet that Mario can use to get rid of the Octoguys.
Gateway Galaxy Planet
This looks a almost identical to the main planet in the Gateway Galaxy but on a much smaller scale. It also has three Goombas living on it. In addition, there is a small gold screw in the ground where the castle would normally be. When Mario spins this screw, the air inside the planet will start to leak out and the planet will shrink as a result. As it gradually gets smaller and smaller, a large ring of coins encircling the planet will be revealed. It will continue to shrink until it implodes upon itself with a small puff of smoke, after which Mario falls back to the Wooden Planet. This planet can only be accessed by shooting Mario out of a cannon at it from the starting planet.
This is a tiny planet with some Cheep-Cheeps bouncing around it. It has a grass and water area with wooden plugs. Mario must pound the plugs to activate a Water Shooter, which will launch him to the Watermelon Planet.
This is a big glass planet with three tennis balls and a watermelon inside it. There is also a Nut-like Sentry Beam here that sends shockwaves around the planet. Mario must avoid the shockwaves and Ground Pound the tennis balls into the watermelon to get the Power Star.
This is a large box to the side of the main planet. It is a large purple box with tubes coming out of it. There is a Boo containing a Power Star and an Urchin inside the box. The box's roof is made of water so it rains inside the box; Mario must destroy the Boo to get its star. This is the area for Deep Dark Galaxy's secret Power Star.
The Underground Ghost Ship
Mario begins on an island with the Toad Brigade already exploring it (They are on a "vacation" although they claim they are searching for Power Stars). The player must jump into the cannon on the center of the island. The player must make sure to point the cursor at the Rainbow Star which will give Mario invincibility to help defeat the many Octoguys. After they are beat, the player must grab the Fire Flower and use the Sling Star to go back to the island. The player should light both urns. Once Mario opens the gate, the player must travel into the cave and must dive into the body of water. Mario must swim deep into the water and the player will find a lever. Mario must Spin to open the gate. The player must swim to the surface. Mario will find a ghost ship surrounded by Boos. The player should go on the ghost ship to fight Kamella. Once Mario defeats Kamella, the player gets a Power Star.
Right after landing on the starting planet, Mario will be confronted by an Undergrunt Gunner blocking the cannon required to progress. To defeat it, Mario can either spin coconuts into it or ground pounding on the cockpit. Then he will obtain the fire flower from the wooden planet, as in the first mission and light three torches to make an Ice Flower appear. Mario will then go across the lake and reach an area full of obstacles, where he will use a Water Shooter to reach the Cheep-Cheep planet. Once activated, Mario can use the Water Shooter to reach a transparent planet that has a watermelon and three tennis balls inside it. Mario must ground pound the tennis balls into the watermelon to make it grow and surpass the glass surface, and the Power Star will appear on the outside of the planet. There are force fields that are generated on both sides of the planet which will electrocute Mario if he touches them.
Guppy and the Underground Lake
The Toad Brigade are worried because Guppy took over the lake, so Mario needs to enter the cave and swim to the bottom of the lake. There he finds Guppy, who tells Mario that if he swims through all eight rings, Guppy will leave the lake. After Guppy swims off, Mario must grab a shell (the extra speed is necessary) and swim after him. If Mario manages to swim through all eight rings in the correct order, Guppy will congratulate him and reward him with a Power Star.
Ghost Ship Daredevil Run (Daredevil Comet)
This mission is accessible only when a Daredevil Comet orbits the galaxy. Mario starts off in front of the ghost ship that is surrounded by Boos. The player will have to go on the ghost ship to fight Kamella. Once Kamella is defeated, the player gets a Power Star. This is the final unlockable boss Daredevil Comet in the game.
Plunder the Purple Coins (Purple Comet)
This level is playable when a Purple Comet is in orbit. The level starts at the Underground Ghost Ship. Once the player collects all 100 Purple coins spread out in the water and on land, Mario will earn a Power Star.
Boo in a Box
The player needs to start the Underground Ghost Ship, Bubble Blastoff or Guppy and the Underground Lake level. The player will have to go to the bottom of the underground lake and Mario must grab a shell. Mario must throw the shell at several mines surrounding half of a ship. The ship will explode, revealing a Launch Star. The player will have to use the Launch Star that leads Mario to a box-like planet. In the planet, Mario will have to Spin next to a arrow in the planet to change the gravity. The player will have to break a crystal which will make light go into the planet. The player will have to lead the Boo into the light to make it give up the Power Star it has.
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