World 6 (Super Mario Bros. 2)

World 6 (known as Chapter 6 in Yume Kōjō: Doki Doki Panic) is the sixth world in Super Mario Bros. 2. World 6 is a desert themed stage much like World 2 but it is harder and has more enemies. In the original game, the boss at the end was Tryclyde, who made its appearance again from World 2, but in the Game Boy Advance remake, Super Mario Advance, it was replaced by Mouser, who is also the boss of World 1. Worlds 6-1 and 6-2 feature Green Birdo, while World 6-3 has Red Birdo before Mouser or Tryclyde.

World 6-1
This level starts like any level from World 2 does: as the desert is explored, numerous enemies and obstacles must be beaten, such as quicksand and swarms of Cobrats and Pokeys. Then a fort is entered, where 21 jars are seen. Only one of them has the key that is necessary to open the door showing Green Birdo's whereabouts. Another jar leads to a 1 UP.

World 6-2
The player has to ride the Albatoss going right until reaching a platform that contains a Magical Potion, which will provide one coin and one mushroom. They then have to ride another Albatoss going to the left until the player reaches a third Albatoss that is above the second one and going back to the left. Finally, the player has to ride the third Albatoss to the end of the screen. Green Birdo is in the cave.

World 6-3
There is a short-cut at the very beginning of the level that will take the player directly to Red Birdo. There is a wall to the left of the top of the ladder with quicksand underneath it. Get up right next to the wall, and let the player sink until just the head is above the quicksand while holding the button to go left. The player should suddenly start moving left. Keep holding left, and start jumping to avoid dying in the quicksand. The player will pass under the wall to reach a door on the other side.

The enemies of World 6-3 include Tweeters, Bob-Ombs, Ninjis, and a few Hoopsters; the environment is cave, desert, and sky. Before battling the boss of World 6, the player must defeat a Red Birdo with a Mushroom Block and eggs. After Birdo is defeated, the player will enter a fight with Tryclyde (Mouser in Super Mario Advance). This level is notable in that no key is found in the fortress, but this is because it was already used in World 6-1.