Super Mario Galaxy/Dreadnought Galaxy
Dreadnought Galaxy is accessible from the Garden observation dome. You need 48 Stars to enter.
 Star 1: Infiltrating the Dreadnought
You start on an hourglass-shaped planet. Use the launch opposite where you start.
This takes you to an area with some helmit-wearing goombas. Kill the goombas by spinning next to them and jumping on them when they are upside-down. Then go in the pipe.
The pipe takes you to a 2nd area. Go right until you find a raised platform between two moving walls. Wall jump to get above the walls. Grab the Life Mushroom on the left. Then run to the right past the moving floors and activate the green switch by spinning next to it. It will turn red, and the level will rotate 90 degrees counter-clockwise. Use wall jumps to get above what are now moving walls, and go right. Activate the green switch. Use the springs to go up and to the right into the pipe.
Jump on the green topmen to get above the rotating cylindars. Stand on the raised platform ahead. You should see a wall moving up and down on either side of it. Use wall jumps to get on top of these walls, then use the Launch Star above.
You will land on a cube-shaped planet. Use the Sling Star opposite where you land.
You will land on a spherial planet with some raised platforms. Flood the planet using a Bullet Bill to break open a cage containing a fountain on its surface. Climb the green staircase, and jump on the moving platform to the right. Keep moving along these platforms to get to the star.
 Star 2: Dreadnought's Colossal Cannons
 Star 3: Revenge of the Topman Tribe
There is a hidden Star here. For the time being, do not enter the pipe on the opposite side of the first flying saucer.
 Star 4 (Speedy Comet): Topman Tribe Speed Run
Same as Star 3, with a six minute time limit.
 Star 5 (Purple Comet): Battlestation's Purple Coins
This Star is rather like Star 5 from the Battlerock Galaxy.
 Star 6 (Hidden): Dreadnought's Garbage Dump
Enter Star 3. At the start of the level, go to the opposite side of the flying saucer where you are standing, and enter the pipe.
Talk to the robot. It will ask you to blow up the trash. You will have 30 seconds to do this. This is similar to, but harder than, Star 6 from the Battlerock Galaxy.
You should be able to blow up all the garbage within the time limit by placing a Bob-omb at each of the five red dots shown on the diagram. The blast radius of each Bob-omb is shown as a circle in the diagram.
Each Bob-omb will blow up ten seconds after you pick it up. That means that any Bob-omb you pick up when the timer is at ten seconds or less will not detonate on its own. If you place a Bob-omb within the blast radius of another Bob-omb, it will detonate; you can use this trick to extend the range of the last few Bob-ombs you place, in case you throw them too far from the target. Alternatively, as long as you pick up the last Bob-omb with more than 10 seconds on the clock, you know that you have quite some time to place it carefully in position - you do not need to throw the last Bob-omb wildly.