Bowser's Gravity Gauntlet

Bowser's Gravity Gauntlet is a galaxy in the game Super Mario Galaxy 2. It is located in World 4. The level is based entirely on gravitational forces. Most of the level is sidescroller, except for the beginning and the end. The level is covered in lava, but there is one part where Mario will need to swim through water to get through the level. Magikoopas are common enemies here and can summon Burn Bits at their will. Firebars are placed throughout the whole level, even underwater. Fireballs also defy gravity because they can change direction in midair. When Mario reaches the end, Bowser will challenge Mario to a battle. Bowser battles the same way he is fought in World 2, except he can create shockwaves and leave a trail of fire.

Bowser's Castle
It is a big fortress where there appears to be almost no gravity at all. At the beginning, there is some lava and fireballs that jump out of it. When Mario enters the castle, he will find more fireballs jumping out of the lava. As he progresses, he will switch to walking in the wall and in the ceiling. After that, there is an underwater section with firebars and Cheep Cheeps. Near the end is a spinning platform and a small section with a Whomp, just before the door before the Bowser Battle Planet.

Bowser Battle Planet
It is exactly similar to the first battle planet. It is a small planet made out of small bricks and a few rocks with coins.