A guide to completing World 6's third Fortress in Super Mario Bros 3 for the Nintendo Entertainment System.

How to Clear World 6's Third Fortress

Go to the right and jump on top of the orb that the two Roto-Discs are spinning around. Then carefully jump on the conveyor belt, which will push you toward the right. Try to land on the orb to the right of the conveyor belt, where another pair of Roto-Discs is spinning around.

Jump past the Boo ghost, onto the conveyor belt, which will push you toward the left. If you are Raccoon or Tanooki Mario, you can run from left to right on this conveyor belt to build up enough speed to start flying. Fly left, up to a platform above the left side of the conveyor belt. Hit the brick there to get a 1UP Mushroom.

If you aren't Raccoon or Tanooki Mario, jump off the right side of the conveyor belt onto a white platform with a Stretch ghost that comes up and moves left and right on it. Avoid the ghost, and hit the ? Block to get a Super Mushroom or Super Leaf. If you got the Super Leaf, you can go to the left side of the conveyor belt, then run to the right to build up enough speed to start flying. Fly left, up to a platform above the left side of the conveyor belt. Hit the brick there to get a 1UP Mushroom.

Jump off the right side of the conveyor belt onto the Stretch ghost platform again, then go right, past another Stretch ghost platform, which has a ghost on the bottom as well as the top. There is a Boo ghost after that, followed by another Stretch ghost platform, which only has a ghost on the top.

Go to the right and jump onto the orb that the Roto-Disc is spinning around. Then there is a conveyor belt that pushes from right to left, with a Thwomp above it. Carefully move toward the Thwomp to make it come down, then try to jump over it while also dodging the Boo ghost and Roto-Disc.

Then jump to the next conveyor belt and get past the Roto-Disc. After the orb that the Roto-Disc spins around, the conveyor belt goes in a different direction. If you are still Raccoon Mario or Tanooki Mario, you can use this part of the conveyor belt to build up speed, then fly left to reach a platform with two bricks. Hit the left brick repeatedly until it stops giving you coins, then do the same with the right brick. Then go back down and fall off of the right side of the upper conveyor belt.

After the conveyor belt, there are two platforms with Stretch ghosts, and there are two Roto-Discs spinning around the hole between the two platforms.

Jump to the ledge after that, then go through the door. You will fall into a room with three Boo ghosts. The wall moves slowly down (or the floor moves slowly up). Stay on the right side of the room while facing the three Boo ghosts so that when the door reaches your level, you can go through it.

Boom Boom

Boom Boom will move left and right, and sometimes he will crouch and slide. Whenever he crouches, his spiky shell is not safe to stomp on. Try to stomp on him when he is running around. You can also hit him with fireballs if you're Fire Mario. After you stomp him the first time, he will sometimes suddenly stop, then jump high up. It can be difficult to aim your jumps correctly when he stops and jumps, so watch him closely. After you stomp on him a second time, he will very quickly run left and right, so jump carefully to avoid letting him bump into you.

After you stomp him a third time, he is defeated, and drops a Magic Ball. Collect it and you will complete the level.

After the Level

The locked door will disappear, giving you access to the castle, where the king has been transformed into a seal (or Monty Mole in certain versions of the game), and Toad asks you to help. You'll automatically enter the World 6 Airship.