Throwback Galaxy

The Throwback Galaxy is a galaxy from Super Mario Galaxy 2 which is a redesigned Whomp's Fortress from Super Mario 64. The music is an orchestrated arrangement of the original Super Mario 64 main theme, as the original version was also played on Whomp's Fortress. Although the course is generally identical, a few minor changes have been made here and there.

New enemies have been added, such as Paragoombas, Skeeters and a Wiggler. Other enemies seen first in the original game also return like Piranha Plants, Thwomps and Whomps. Some Bob-omb Buddies also appear in the galaxy, and even make reference to how Mario seems familiar, a reference to his earlier visit to Whomp's Fortress in Super Mario 64 and its remake. A Whomp is found at the top of the area, and defeating it will open an area where the Whomp King is found. A Comet Medal, Rainbow Notes (released from breaking a crate, playing the Super Mario Bros. underground theme) and a bonus planet featuring Piranha Plants can be found in the stage too. Several Cloud Flowers also appear in the galaxy's second mission.

Whomp's Fortress
A planet almost identical to the course with the same name in Super Mario 64. However, the floating islands that contained Red Coins are no longer found. There are a lot of enemies, such as Thwomps, and Piranha Plants in this planet, and at the top Mario can defeat a Whomp to access the Whomp King's Planet.

Whomp King's Planet
A square planet where the Whomp King is battled. This time, however, Mario can fall from the stage and lose a life. The Whomp King is also much stronger than he was before. It is under the Whomp's Fortress.

Return of The Whomp King
The first mission here is very reminiscent of the same mission in Super Mario 64 and its DS remake, with a few minor changes. Now, when the player gets to the top, he battles a regular Whomp, which, due to the size changes in the species between Super Mario 64 and Super Mario Galaxy 2, appears to be more or less identical to the original Whomp King in size. The biggest difference between the first star in "Chip off Whomp's Block" and the first star of "Throwback Galaxy" is, upon defeating this Whomp, a hole opens up in the center of the platform, which the player must then drop down to get to the planet's underside, where the player fights the now even bigger and much tougher Whomp King.

For various reasons, the Whomp King is more difficult than his original debut appearance fourteen years prior. His size is much larger than before, due to the fact that normal Whomps are about the size that he was in Super Mario 64. Because of his size, he also can walk around the battlefield much more quickly than before. The area he will slam down on is now highlighted in red. The Whomp King also has some new attacks, which also make him more difficult. For one attack, he does a short hop, which will stun Mario or Luigi if they are on the ground. This shockwave also occurs when he slams down as his primary attack. A second is when he stomps his right foot down, and a group of Whimps appear from the ground. However, these don't make much of a difference to the battle, as the Whomp King will more or less likely destroy the Whimps himself anyway. He is harder to get on top of, as his increased thickness makes the flat surface of his back higher up than it used to be, so Mario will likely have more trouble getting the chance to attack him than before. Instead of being able to Ground Pound anywhere on his back to damage him, the player must hit a small imprint on his back. When defeated, he will recite the same speech as in the original Super Mario 64, as well as then hitting the ground while muttering "Dang it!" under his breath, before exploding and handing over the Power Star.

Silver Stars in the Whomp Fortress
There are Cloud Flowers and five Silver Stars added in this level. With the help of the Cloud Flower, Mario/Luigi needs to get all the Silver Stars in the galaxy, so he is rewarded with a Power Star. The Whomp which defeated leads to Whomp King is replaced with two Paragoombas.

Whomp Silver Star Speed Run
This is Throwback Galaxy's Prankster Comet. The stage is the same as Silver Stars in the Whomp Fortress, only there is a time limit of two minutes. If Mario or Luigi grab the five Silver Stars before the time ends, they gain a Power Star.

Green Star 1
This Green Star is found in the Whomp Fortress. The player must make their way to the moving platforms. It is right below the last one. They have to fall carefully to reach it.

Green Star 2
The Green Star is found on the Whomp's Fortress's top. The player has to wait untill the Whomp is near the star, then perform a Wall Jump on it to reach the star.

Green Star 3
This Green Star is found far out in the skies of the fortress, near the clouds with coins and a Silver Star. The player must use Cloud Mario's clouds to reach it.

Trivia

 * The new version of the theme that plays here is now jazzier than the original.
 * The cannon is replaced with a Sling Star.
 * It is possible to reach the bonus planet without teleporting by using a Cloud Flower. By doing this the player can defeat the enemies in the stage and get three 1-Up Mushrooms without a time limit. But the player will be stuck in the planet and they will have to exit the galaxy or lose a life.
 * The galaxy got its name because the player is thrown back into a memory of the older game, Super Mario 64.