I loved the lava levels

The wind garden galaxy was rad in both gameplay and music.

Gusty Gardens, by far.  Amazing music, amazing scenery, amazing textures on all the different planets, just everything combined into an AWESOME level.

Same, gusty gardens. Either that or the 2nd bowser level..

The Honeyhive Galaxy is the one I go back to if I want to pop the game in for a few minutes and just play a couple of levels.  It could also be because my 4 year old son has the spiel by Toad at the end of the first level memorized.  "AAAGH!! A BEE!!  Oh Mario, it's you...."
I also really enjoy that little tune.  I also like the music from the Beach Bowl Galaxy.  I think though like everyone else Gusty Gardens has the best music in the game almost without question.

Battlerock was my favorite.

"Gusty Gardens"

The last level.

Cinematic perfection during gameplay.

im gonna have to go with gusty gardens too. the music was just awesome. the level just looked so great too.

I like the lava levels the most. They seem the most challenging even though it only took me one try to get through them. That 2D bowser level was cool too.

I agree, you can't beat the music in Gusty Gardens though its awesome.

While it's not a world, my favourite part of the game was the Luigi space where you had to get the 100 purple coins.
Challanging, yet fun.

I liked the Freezeframe Galaxy that has ice and lava also Toy Time Galaxy and Gusty Garden Galaxy.

Gusty Gardens, I also actually love the music in Good Egg galaxy, it gave a great intro to the game.

That one lava level, the one in Mario Galaxy Fan's icon.
I'll just go with the japanese name of the level, hell prominence (no wonder they changed it outside of japan)

But yeah, that's my favorite one, just because of the challenge.

The  bee level is very cool

Beach Bowl Galaxy.

I <3 Teh Penguins.

Probably Space Junk Galaxy. I like how you float around in space in that Galaxy.

My favourite though is the Gusty Garden Galaxy. It had amazing level design fantstic music and was just fun to play.

While i absolutely love all of the levels, the bedroom is my particular favorite, mostly because gravity never stays still, also i love all bowser/jr. levels, as well as the trials.

The Toy Galaxy was my favorite.

Earth

I loved the water race, it truly amazed me how beautiful that was

"I loved the water race, it truly amazed me how beautiful that was"