The gameplay will be similar to other 3D games but more linear, like in Super Mario 3D Land. The levels and worlds will have themes, like the New Super Mario Bros. games. The worlds will have individual names and will be connected, like in Super Mario World. Stars also replace the flags.
- Koopalings (all 7 + Bowser Jr.)
- Dino Piranha
- Giant Crabber
- King Boo
- Petey Piranha
- Sir Starfish
The game has several stages known, broken up here into theme.
Grass (Probably World 1)
- World 1-1: A stage with a lot of Goombas and Koopas. It has several pipes. Dino Piranha is faced at the end.
- World 1-3: A grassy level with the Cloud Flower, being used the same way as in SMG2.
- World 1-6: A pipe level with lots of Piranha Plants. Petey Piranha is faced at the end.
- A cave with sand geysers and sandfalls. It is infested with Pokeys and Spinies.
Ice (Probably World 3)
- World 3-6: A level high in the sky with several icy platforms and rotating stars.
Water (Probably World 4)
- World 4-4: An underwater level with lots of Cheep-Cheeps and Bloopers. Sir Starfish is faced at the end.
- World 4-5: A beachy level with lots of palm trees and a raft. Giant Crabber is battled at the end.
Cave (Probably World 6)
- World 6-1: A cave level with brick blocks and lots of Fire Enemies.
- World 6-6: A cave level with some water and a lot of Cheep Cheeps.
- World 6-7: Another cave level where Mario starts outside. It has a lot of pipes and bricks.
Lava (Probably World 12)
- World 12-4: Two identical towers that are close to Bowser's Castle. Mario must climb the towers using ladders and platforms placed strategically. It has the new stick enemy and a new spider enemy. Lava is found throughout.
- World 12-7: A level with raining meteors and brick block platforms. P-Switches must be used.
Sky (Probably World 8)
- World 8-8: A level on really high platforms that spin around. Giga Lakitu is faced at the end.
- World 6-Ghost House: A ghost house with several doors that lead to different sections of the house. King Boo is faced at the end.
- A tower with Dry Bones and a new stick enemy that can whack Mario. Fiery Dino Piranha is the boss.
- A castle with moving platforms across a lake of lava and some Magikoopas. Larry Koopa is battled at the end.
- A tower with lots of Thwomps that need to be wall-jumped off of. Sorbetti is battled at the end. This could possibly be the World 3 Tower.
- A castle with three paths that can be taken, each hard in its own way. Roy Koopa is faced at the end.