Supermassive Galaxy

Supermassive Galaxy is the first galaxy of World 4 in the game Super Mario Galaxy 2. This course depicts many common Mario enemies and elements at an extraordinary size, including Piranha Plants, Lumas, coins and platforms. The concept can be compared to that of Giant Land from Super Mario Bros. 3 or the 'huge' part of Tiny-Huge Island in Super Mario 64.

The Supermassive Galaxy music theme is a remix of the Toy Time Galaxy's "Super Mario 2007" from the previous game, which in turn is an arrangement of the overworld theme from Super Mario Bros.

Planets
NOTE: Unless otherwise noted, all names are unofficial.

Starting Planet
The Starting Planet is a series of platforms made of giant Blocks, Brick Blocks and Warp Pipes, as well as a single ? Block and a giant spinning coin. A giant Luma is found next to the starting point. The player will encounter Giant Goombas roaming around and Super Piranha Plants guarding the pipes. The Comet Medal can be spotted over a gap near the giant coin.

The backmost section of the planet is a row of big blocks where Mario must avoid two Big Thwomps and gaps under them; the Launch Star is accessible right ahead. The player may also long jump off the top of the first Big Thwomp; performing a spin, they can break the gravitational pull and land on the Giant Koopas Planet.

Giant Koopas Planet
This small, circular dirt planet is the second planet that players visit and the only sidescrolling portion of this galaxy. It is populated by three Giant Koopas that continuously walk around it counterclockwise. It is similar to Digga-Leg's planet in the Spin-Dig Galaxy, also containing a Spin Drill that the player must use to defeat the three Giant Koopas in order to reveal the Launch Star.

On this planet, if players can jump repeatedly on any Giant Koopa shell eight times in a row and then continue to do so, they can earn extra lives until the maximum of 99.

Giant Warp Pipe Planet
This planet is not accessed, but Mario flies through it after being launched by the second Launch Star from the Giant Koopas Planet. There are Star Bits on its inner walls.

Giant Star Chips Planet
Like the starting one, this planet's terrain consists of giant blocks, pipes and other objects. The first section is a bridge made of large Star Chips. Another giant Luma is seen here, as well as Big Paragoombas and more Super Piranha Plants ahead. At the end of the planet there is a series of giant elevators that disappear and reappear constantly, which the player must traverse with timed movements. The Launch Star here will take them to the Blooming Garden planet.

Blooming Garden Planet
When the player lands on this planet, it is a simple, grassy sphere. However, as Mario walks around it, flowers start to appear and bloom from his steps. When the flowers completely cover the planet, a vine sprouts, allowing the player to reach the hidden Power Star and complete the mission. A Launch Star to the Stone Tube Planet is available at all times.

Stone Tube Planet
This planet is shaped like a cylinder made of stones and is inhabited by Big Wigglers, the last two being enraged and running at a faster pace than the others. The player can get past them by using the Long Jump. The Power Star for Huge Trouble With Big Wigglers is located on top of a pole at the end of this planet.

The Stone Tube Planet bears resemblance to the Cyclone Stone in the Beach Bowl Galaxy from Super Mario Galaxy, which appears later in this game in the Stone Cyclone Galaxy.

Green Star 1
The player will redo the Huge Trouble with Big Wigglers mission. The first Green Star is located on the first planet. The player has to perform a triple jump off the edge of the giant coin to get it.
 * Planets Visited

Green Star 2
The player will redo the Huge Trouble with Big Wigglers once more. The second green star is located below the second Brick Blocks found where the Big Thwomps are falling. The player has to fall carefully to get it. If they miss the star, they lose a life and must restart from the beginning. An alternate, but riskier way, is to long jump from the green pipes on the opposite side.
 * Planets Visited

Green Star 3
The player will redo the Huge Trouble with Big Wigglers for the final time. The final green star is located on the Giant Koopas Planet. The player has to perform a triple jump to reach it or, alternately, jump on one of the Giant Koopas and bounce up to the Green Star.
 * Planets Visited

Prima Official Game Guide description

 * "Supermassive is composed of planets and enemies from previous adventures, but everything has been gigantic-sized. Though larger than you, these enemies are still vulnerable to your attacks so do not let their size scare you from questing for the Power Stars."

Trivia

 * As presented in E3 2009, the Blooming Garden Planet was originally grassless, and there were regular Goombas on it.

Gigagumba-Galaxie