Super Mario Galaxy 2/Bowser Jr.'s Fiery Flotilla

Items
The comet star is located on top of the whomp in the first area and is very hard to get. Jump on top of the ? block in fron of the whomp and do a backflip to land on top of the whomps head. Once the whomp raises, jump and grab the comet medal. While you are on top of the whomp there are still more things you can do. When on the whomp, backflip towards the castle's wall to land on top of it. A one up mushroom can be found up there. In the second area there is a life mushroom next to two rotating fire wheels.

Star 1: Gobblegut's Aching Belly
Follow the path until you reach the large doors. Flip the switch near the area to open them. Proceed past the dry bones and ride the launch star into the second area. Avoid the fire wheels and follow the path to the launch star. You will land on the area with the boss. To kill the boss use your spin attack on all of the red bumps on its body. This is much more difficult than it seems. Once the boss is defeated, grab the shiny power star.