World 3 (New Super Mario Bros. Wii)

World 3 of New Super Mario Bros. Wii is an ice-themed world conquered by Lemmy Koopa. The Penguin Suit is introduced in this world. This is also the first world in the game that has a switch that can change the obstacles slightly in levels, similar to Switch Palaces. On the map is an area with ice that has two Ice Bros. on it. If Mario and the gang are hit by them, they will endure a battle game where they will have to complete the Enemy Course.

3-1 Cooligan Ice Slope
This area is infested with Cooligans.The first part is pretty simple, but the second part isn't.

3-2 Snowy Bullet Bills
This is a snow level that is infested with Bullet Bills.

Enemy Course

 * Two Ice Bros.
 * Three Ice Bros.
 * Four Ice Bros.

The Ice Bros. will throw ice balls that will freeze and damage Mario and crew. To quickly escape an ice entrapment, simply shake the Wii remote.

3-3 Cold Crevice
This is an icy cave level wit 3 parts there are falling icicles, giant falling icicles that Mario can walk on, and some annoying enemies like Swooper s.

World 3 Ghost House
This is the first Ghost House in the game, Big Boos, little boos, and possessed furniture are the main obstacles in this level.

World 3 Tower
A portion of this level resembles Castle Crush, A level found in World 6 of Donkey Kong Country 2. This level features brightly colored rotating blocks that must be used to climb to higher locations. Rolling spike balls, Dry Bones, and Amps are some of the hazards that must be avoided as the floor scrolls upward.

3-4 Ice Block Bananza
When Mario first does this level, he can only get to the secret red flag that takes him to 3-5. After hitting the Red Switch after 3-5, all the red blocks will appear letting Mario beat the level the regular way.

3-5 Freezing Fungus
When Mairo does this the first time he can only reach 1 of the 2 endings, however if he returns after hitting the Red Switch, red blocks will appear and he can reach the hidden ending, unlocking a starman house.

World 3 Castle
Lemmy's Castle is riddled with giant falling icicles and frozen floors making timed jumps difficult, there are also some segments with bottomless cliffs which are traversed by a moving raft similar to the ones seen in Roy Koopa and Larry Koopa's castles in Super Mario World however this one is frozen. This is also the first level to feature Bob-ombs.