Bowser Jr.'s Boom Bunker

Bowser Jr.'s Boom Bunker is a boss galaxy in Super Mario Galaxy 2. Here, Mario will fight Bowser Jr.'s most dreaded weapon, the Boomsday Machine. The main enemies here are Octoombas and Chain Chomps.

Ruins of Megahammer Planet
The starting planet of the galaxy. There is a lot of mud in this galaxy, a few Fizzlits and a Chance Cube. The Megahammer that Mario fought earlier in the game (or possibly another) is found destroyed. A single Bullet Bill still pops out of its blaster. There is a crystal vault protecting a Cannon on top of the remains of one of the robot's arms.

Boomerang Bros. Planet
A castle-like planet inhabited by two Boomerang Bros. There is a big target on one side. If Mario hits on the center when launched from the cannon he will get a 1-Up. There are several poles in the planet, and one of them has an Life Mushroom at the top. After defeating the enemies, a Launch Star will appear.

Midway Planet
A small planet with a Midway Point and some spikes spinning around a cannon.

Spinning Platforms Planet
A planet with a Black Hole inside of it. There are several spikes and different colored platforms spinning around at different speeds. The second set of platforms have Mines on them and a Comet Medal in between two mines. There are also a few Cloud Flowers here. At the end is a Launch Star.

Dark Matter Planet
A big, rectangular planet with a few platforms floating in dark matter. There is a platform that tilts and moves while carrying Mario. At the end are a Midway Point and a Launch Star. This planet replaces the Spinning Platforms Planet in the Daredevil Mission.

Boomsday Machine Planet
A circular planet made where Bowser Jr's Boomsday Machine is battled. There are some air vents, clouds and Cloud Flowers throughout it.