The Throwback Galaxy is a galaxy in the game Super Mario Galaxy 2. Based on Whomp's Fortress from Super Mario 64/DS, this galaxy has the same landscape, structures, and layout as the original, along with the first mission's characters saying exactly the same things they did from Super Mario 64 and its DS counterpart.
Return of the Whomp King
The mission is similar to that of Chip off Whomp's Block from Super Mario 64. Mario or Luigi must climb to the top of the fortress and defeat a Whomp residing at the top of the level. However, defeating the Whomp results in a trap door opening, something that did not happen in the original level. Going down the trap door leads to a fight against the real Whomp King, who is much more difficult than he was in Super Mario 64. Beating him allows Mario or Luigi to get a Power Star.
Silver Stars in the Whomp Fortress
Whomp Silver Star Speed Run (Speedy Comet in Orbit)
This mission is identical to that of Silver Stars of Whomp Fortress, except Mario or Luigi must beat the level under a time limit. Mario and Luigi must collect the Comet Medal in Return of the Whomp King before they can access this mission. This mission is only accessible, unless already completed, if a Speedy Comet is in orbit.
Green Star 1
The first Green Star is located in the pit under the retracting platform furthest from Mario's starting position. It can be collected in the Return of the Whomp King mission.
Green Star 2
The second Green Star is located in the air at the top of Whomp's Fortress. Mario must utilize the Whomp to obatin it.
Green Star 3
To get this Green Star, grab a Cloud Flower and make it to the part with the spinning bridge. Walk across the clouds and long jump to the one in the middle, trying not to use a cloud. Long jump off the edge and make a cloud 3 times to get it.
The Whomp King is placed to the bottom of this galaxy. When at the top of this galaxy, Mario (or Luigi) will see a Whomp and stomp it. On the top there is a circular Bowser sign. When entered, they will land to the bottom part of the galaxy. The Whomp King will await one of them. He will be a lot more difficult than before. Also, there is a Bob-omb Buddy at the beginning of the stage. The place where the Power Star gained from collecting eight Red Coins appears in Super Mario 64 was replaced with a teleporter to a bonus arena where Mario or Luigi must fight enemies. In the same place as one star in the other games contains the Comet Medal of the galaxy. The cannon was replaced with a Sling Star that throws Mario or Luigi up in the air allowing them to get Star Bits. For the second star, there are clouds added to the stage where the brothers collect five silver stars. There are minor differences in the land structures since this galaxy is the same as Whomp's Fortress. Also, unlike the N64 original, Hoot the Owl is not in the tree next to Mario's starting position, but a 1-up Mushroom is directly above it.