Starting Planet (Megahammer's Junkyard: A planet that is covered in mud. Bowser Jr.'s Mighty Megahammer can be seen buried in the northern part, where Mario starts off.
Boomerang Bro. Planet: Boomerang Bros. can be fought on this square-shaped planet.
Cannon Planet: A small planet that has a cannon that leads to the Spinning Platforms Planet.
Spinning Platforms Planet: A planet that has multiple spinning platforms. Mario cannot access this planet if he does the Daredevil Comet mission.
Dark Matter Planet: Dark Matter lair here, forming a "sea" that covers the flat planet they make their home on. Mario has to use a raft to make his way past their colony without touching them, lest the monsters devour him, taking one of his lives away. Mario can only access this planet during the Daredevil Comet mission.