World 4 (New Super Mario Bros. 2)

World 4 is the fourth normal world in New Super Mario Bros. 2. It is a snow-based world, and the levels are made up of snow or ice. The map music is the same one which was used in World 3 of New Super Mario Bros. Wii. This level is unlocked when a player completes World 3-Castle. This is also an optional world as the player can choose to go to World Flower instead.

There are 12 levels and 4 Toad Houses in this world. Of the 12 levels, 8 levels are on the main path, which includes 5 normal levels, a Ghost House, and the Fortress and Castle. Of the remaining four levels, one is the Rainbow level, one is a level requiring payment of Star Coins and the other two are secret levels. Of the 4 Toad Houses, one is red, two are green and one is yellow. The boss of this world is Morton Koopa Jr., who is fought at the castle level.

Levels

 * World 4-Rainbow
 * World 4-1
 * World 4-Ghost House
 * World 4-2
 * World 4-A
 * World 4-Fortress
 * World 4-3
 * World 4-4
 * World 4-C
 * World 4-5
 * World 4-B
 * World 4-Castle

Trivia

 * Some levels in this world have a jagged mountainous background that is similar to those found in several levels in Super Mario World.