World D

World D is the fifth and final secret world that was featured in the game Super Mario Bros.: The Lost Levels. Like the other secret worlds, it was left unused in Super Mario Bros. Deluxe.

Enemies

 * Hammer Bro.
 * Green Paratroopa
 * Bill Blaster
 * Bullet Bill
 * Red Paratroopa
 * Green Koopa
 * Red Piranha Plant

World D-4
When Bowser is defeated, Princess Toadstool is saved, and, as such, Mario and Luigi beat the game.