World A

World A is the second secret world that was first featured in the game Super Mario Bros.: The Lost Levels, coming after World 9. The Koopa Troopas from this world on move faster than the normal ones.

In the Famicom version of Super Mario Bros. 2, the player must beat the game eight consecutive times and hold down the A button on the title screen in order to access World A, and in turn the other letter worlds. However, in the Super Mario All-Stars remake of the game, the player simply has to beat World 9 in order to access the letter worlds. World 9 and the letter worlds were left unused in the Super Mario Bros. Deluxe version of the game.

Level maps
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Screenshots
File:WorldA-1SMBTheLostLevels.png|Luigi and some Koopa Troopas in World A-1. File:WorldA-2SMBTheLostLevels.png|A 1-Up moving along the bricks while Luigi is trying to get it in World A-2. File:WorldA-3SMBTheLostLevels.png|Cheep-Cheeps along with the heavy wind while Luigi is collecting coins in World A-3. File:WorldA-4SMBTheLostLevels.png|Luigi jumping over the bed of lava right before the fight with False Bowser in World A-4.