Create your own level(s)!

My level would be in SMG2. It's the last level, and Bowser has unleashed his last and most deadly weapon: Mega-Yoshi. A massive, nuclear Yoshi that Bowser plans to use to conquer all of space. It's as large as a tall building, so Mario must climb and jump off anything jutting out the monstrosity while Yoshi shakes around and shoots giant lasers from his eyes at you, much like a Colossus battle in Shadow of the Colossus.

When you get to the top of Mega-Yoshi's head, you feed him a fruit from your pocket and he turns nice. You ride the monstrous Yoshi though Bowser's castle, blowing up everything in your path, until you reach the heart of the fortress, where Peach is being held. Yoshi shoots open the cell holding Peach just as Bowser appears, all suped up in nuclear form too. Mega-Yoshi and Giga-Bowser do battle jumping, punching, and shooting laser and fire at each other. At the end of the fight, Bowser crumples to the ground, exaughsted. Mega-Yoshi swallows him, shoots out the egg, and crushes Bowser with it's feet.

Mega-Yoshi shrinks back into a normal Yoshi as the nuclear powers wear off, and Mario takes Princess Peach into his arms and rides atop Yoshi out the crumbling castle, as the player must doge giant flaming rocks and chunks of the falling ceiling. They escape, Mario and Peach make love, and the cycle continues.

I'd love though if Nintendo gave you the feature to edit levels and share them with others.

As for a level, I'd probably think of a Mario Kart game where you are Ice Skating and you need to beat the other 11 competitors (online play maybe).

i have one for yoshi's island

world 2(sky world)-4 (castle)

at the start of the level, a giant spiny shell falls from the ceiling and rolls forward, and yoshi has to run away from it until he gets to the end of the castle. instead of going through a red door, yoshi stops at a dead end, but fortunatly, the spiny slows down and stops. a wall on the left side of the dead end falls down and the giant spiny unwravles. a small lakitu apears in the air. kamek appears and turns the lakitu a LITTLE BIT bigger and the walls have spikes. yoshi has to throw eggs at spinys face and ground pound it when it knocks over 3 times while avoiding the giant, (but not as giant as the boss) spinys that lakitu throws. lakitu dies when yoshi ground pounds the spiny a 3rd time and the spiny knocks into it.

Psst, there's a fan project called Super Mario Galaxy 2.5, you can put ideas there.

Anyways, here's my galaxy...

Background- Slipsand Galaxy
Music- Gritzy Desert theme

Snaky Sandy Galaxy-

Star One- Snaking and Dashing

The beginning is a round planet with a bunch of Goombas and Pokeys, defeating them all will bring up the Launch Star.
The next part is full of quicksand, and the way across is a bunch of Snake Blocks. There are those skull and crossbone signs in front of the blocks. A regular sign says- "Keep up!" The blocks go noticeably faster (can you do that?) than normal, and they make sharp turns and move in a way that requires Long Jumps to get across. Sometimes, walls have to be jumped over. There are Dry Bones that fall down onto the Snake Blocks that stay there for Mario to avoid. A few Paragoombas also hang around the path in Mario's way. *checkpoint and Launch Star*
Mario lands on a planet with seven Ground-Pound Switches. Six of them spawn Pokeys, and one makes a Launch Star pop up. The Launch Star sends you to the next, quicksand-filled planet.
At the end, you get on that Sand Sailer from Slipsand's second mission (what's it called?) and go on it towards the next Launch Star. There are more of those skull signs.
Dry Bones still drop down from who knows where, and there Paragoombas are still in Mario's way. Bullet Bills are fired on the way by Undergrunt Gunners that Mario has to dodge, while keeping up with the cacti that are crushing parts of the sandship. At the very end, there is a Launch Star that's reachable only by jumping on a huge moving platform with the Undergrunts STILL after you.
And the end, there is an extremely fast Snake Block path.
*checkpoint*
Fortunately, there's a Yoshi Egg and Dash Pepper. The Blocks barely turn, and inch a little to the left or right, making a curved path. Before your boost runs out, you need to snag another Dash Pepper.
The Star is on a tiny platform that has a few crystals containing Star Bits. There are a few moving blocks in Yoshi's way (the ones in Slipsand's first mission), and you need to make your way around those blocks

Star Two- Silver Stars and Cosmic Clones

The entire level is just one big Snake Block path with Cosmic Clones, and the Dry Bones fall onto the blocks less often. The Snake Blocks go slightly faster than the last mission, but to counteract that, there are less sharp turns and less Undergrunt Gunners. The Path has Ground Pound switches along the way to both kill off the clones and slow down the environment like the switches in Stone Cyclone Galaxy. Silver Stars must be collected along the way, and when they're all collected, the Star appears. When you die, you lose the Silver Stars you collected and you have to restart from the Ground-Pound Planet. To make thing interesting, a new batch of Clones pop up when a Silver Star is collected. There are no checkpoints in this area of the level, so you need to be careful and not mess around trying to mess around with the clones or anything else stupid. When you reach the end, there's a switch to kill off the Clones, and then you go up a bunch of blocks to find the Star.

Prankster Comet- Speedy Snaky Foes
(Fast Foe)

You basically just redo the first mission under Fast Foe conditions, and there are no walls to block the way on the Snake Block Path. The first planet is replaced with a bigger planet with Star Chips and Pokeys. Getting the Star Chips sends you to the next area.

Read more: http://supermariogalaxy2-5.com/index.cgi?board=extralevels&action=display&thread=683#ixzz1hZd69A7T

I am just so addicted to this game that I've been thinking of lots of ideas for new galaxies. Of course, some feautures are impossible in both SMG and SMG2, but it's the only way I can think of a whole lot of galaxies without anything similar to other galaxies from the two games. I'll try to add on to these later.

1. Turbo Speed Galaxy

Star 1: Speeding the Bullet

You'll land in a small metallic plane. Since this is the first galaxy of the game, it's quite easy. A luma will tell you the basic controls, then transform into a launch star. You will land in a grassy plain. It's a planet with a black hole under it, falling means death. There are a total of 8 Octoombas that you need to defeat for the launch star to appear.
You will land in a small rock planet. There are three other rock planets you can easily jump to in order to collect 5 star chips for the launch star to appear. You will then land in a 2D planet similar to Honeybloom Galaxy in SMG2, but in a different style and size. It is a grassy planet with a few Octoombas and Piranha Plants, as well as some gaps to jump. You will eventually reach a launch star to another brown planet with a Bill Blaster. You must direct the bullet bill to the cage in the middle to destroy it, revealing the final launch star.
You will land on Bullet Road, where Rocket Bill resides. Bullet Road is a long road that is destroyed when Rocket Bill blasts through it, so you are being chased by him. There are a few gaps and obstacles to jump on, as well as a few Octoombas, but other than that, it is a really easy path and you will have no trouble avoiding him. There is a giant metal block at the end, where the road eventually turns right. Go right, and Rocket Bill will continue forward, smashing into the metal block, and revealing a Power Star.

Star 2: The Mythical Dino Egg

You will begin in the same planet you were on, but there will now be a Yoshi Egg waiting for you. On the opposite side of the egg is the launch star to the same grassy plain, but it now has two Smeeches and some Flipbugs, as well as some fruits to eat. There is now a big fruit at the end that must be pulled to reveal the launch star. This will take you to a new planet, the Rock Mountain planet. With Yoshi's flutter abilities, he should be able to scale the mountain with ease. In the near top, there are a few Flower Grapples that needs to be used to get to the launch star. This will take you to the final planet, which takes the use of Flower Grapples farther. You will arrive in a small metallic platform. Use the flower grapples to get through. Once you reach the fourth metallic platform, you will find a bill blaster. You must then use the remaining flower grapples to avoid the bullet bills and reach the Power Star.

Star 3 Prankster Comet: Bullet Road's Purple Coins (Purple Comet)

You will land on Bullet Road, where you have to avoid Rocket Bill again, but this time while collecting purple coins along the way. There are a total of 30 purple coins that needs to be collected to earn the Power Star.

That's it for now. I have like 10 others, no time to type them right now.

I have a whole game basically... But okay, here are some levels for you.

Bad Egg Galaxy
When Snacks Go Bad
You start off on a normal planet, just like every other first world. Go to the other side of it and there will be a launch star. After numerous grass-filled, lush, watery planets, you will come to a large, Dino Piranha-esque egg. Upon cracking it, fumes will spit out, contaminating the planet, and bringing a quite forgiving time limit. Dino Piranha (Mutated) then fights you. It is the exact same battle as the first game, but he can shoot radioactive sludge at you.
Cleaning the Kitchen
In this mission is is your job to clean up the mess Dino Piranha left around the galaxy. Using water balls (Retextured coconuts that explode with water when hitting the ground), you have to clean up each planet until it is spotless. A launch star appears in each place, until you get to the final planet, where you are awarded your star.

I think I will leave you with that, have fun with it.