World D-3 is the third level of World D in Super Mario Bros.: The Lost Levels.
Layout
The player begins next to a bunch of six Turtle Cannons, and in the third slot between them is a brick with a power-up. After a pipe with a Piranha Plant, there are two Hammer Brothers. that will accuse at the player. Before the next Turtle Cannon, there is a row of Hidden Blocks that can be old as cover against the next bunch of Hammer Brothers. After another bunch of six Turtle Cannons is a Springboard that the player can old to reach the top of a pillar with a Red Koopa Troopa on it, which can be used to hit the Hammer Brother below. Next is another Piranha Plant, three more Turtle Cannons, two Hammer Brothers, and a Koopa Paratroopa before Turtle Cannons in a stair generation that directs to the flagpole.
Enemies
| Name | Count |
|---|---|
 Turtle Cannon |
20 |
| Bullet Bill | (infinitely spawned from Turtle Cannons) |
| Piranha Plant | 2 |
| Hammer Brother | 7 |
| Red Koopa Troopa | 1 |
| Green Koopa Paratroopa | 1 |