The Big Bad
Bowser will be the Big Bad... at first.Mario and co. go through eight worlds and defeat him, as usual. After that, the credits roll, and everybody lives happily ever after, right? Wrong. Another villain comes out of the woodwork, and forces the heroes to go through eight more worlds with harder levels, not unlike Luigi's kidnapping setting up the Special worlds in Super Mario 3D Land. The identity of this new bad guy would either be Dry Bowser or, you guessed it, Wart.
There's a level editor in this game.
This game will also be made for the Nintendo 3DS.
At the end, the entire game will turn out to be All Just a Dream.Just like the previous game that featured Peach and Toad as playable characters.
King Boo will be in this game.Probably as a boss.
The world map will be based on the original Super Mario 3D Land, with elements of the one from Super Mario Galaxy 2.Specifically, you select the worlds in the same manner as in SMG 2, and there are branching paths in the maps (thus allowing for secret exits like in the New Super Mario Bros. games).
The Frog Suit from Super Mario Bros. 3 will make a comeback.
The Koopalings will return.
The reason that Peach is helping is because she's angry that Bowser kidnapped another Princess.Hey, she's gotten used to the attention over the years.
If the Special Worlds from 3D Land return, they will take place in the Mushroom Kingdom, since the main story seems to take place in a new land.
The final fight with Bowser will involve him getting his own Cat Suit.The suit will look more like a lion or some other big cat, and he will use it to chase the player up walls and across platforms.
The "Shiverburn figures," Super Mario 3D Land ghost house figures, and/or the UFO will be more directly involved in the game, or at the very least this will continue with the cryptic Easter Eggs.Super Mario Galaxy 2 brought us the figures, and 3D Land (which, by the way, is made by the same team that did Galaxy 2) has both a UFO seen in 1-3 and a ghost looking... thing in the yards at the end of every ghost house level. 3D World, both being made by the same team as said two games and seeming to be heading up to at least something with the hidden Comet Observatory in the full concept art, might just actually be going somewhere with this.
Rosalina is playableA few people have determined Rosalina is featured amongst the game's stamp collection. Interestingly◊, she seems to have a player icon like Mario, Luigi, Toad and Peach, suggesting she too is playable. Makes sense when you consider the Comet Observatory cameos and she could easily share Peach's ability of being able to float.
The two Luigis in the Luigi Bros. game......are the same two Luigis from Super Mario Galaxy.
The Fairy Kingdom is Subcon.The Cherries are there, there are a lot more cloud platforms in this area, and it has Toad and Peach (And Rosalina) as playable Characters.
Bowser kidnapped the Sprixie Princess so they could build World Bowser for him.The Sprixie Princesses all seem to have the magic power of being able to build pretty much anything from scratch, including a rocket ship. Bowser may have forced them to build them an egomaniacal amusement park, or somehow stole their magic and built it himself.
Some of the jazzy tunes in this game are among the ones that were rejected for Super Mario Galaxy.Interviews with Koji Kondo and Mahito Yokota indicate that Yokota originally came up with many jazzy, Latin tunes with some steel drum and synthesizer elements for Galaxy, due to him being under the impression that this fit with the typical Mario game sound. But Kondo rejected it, and they instead went with the more orchestral approach to the Galaxy soundtrack. However, they and Shigeru Miyamoto probably figured that it would be a shame to just scrap what Yokota had composed originally, so they decided to save those jazz songs for a later Mario game which they would fit better with.
The Sprixie Princesses were being rescued in order from youngest to oldest.Much like how you fought the Koopalings in order of age in Super Mario Bros. 3. This also continues the theme of the green sibling being the youngest and the red sibling being the oldest.
Captain Toad is ToadThe playable Toad wears a blue hat and blue vest, while the "main Toad" of Mario usually wears a red hat and blue vest. Thus, we can figure that 3D World Toad may not be "main Toad" and that Captain Toad, as he is a unique character with a red hat, is the main Toad
The playable blue Toad is actually the same one from the Toad Brigade.Supporting this is the fact that the other brigade members (the green, yellow, and purple Toads) are running item houses. Also supporting this is the fact that they, along with the captain, are seen traveling together through a clear pipe in the credits.