A guide to completing the World 1 Fortress in Super Mario Bros 3 for the Nintendo Entertainment System.

How to Clear World 1 Fortress

Go to the right, but beware of the Podoboos that jump out of the lava pits. You can hit the ? block to get a Super Mushroom or Fire Flower.

Keep going to the right, past another lava pit and Podoboo, and you reach a hallway with a spinning Roto-Disc. Don't let the spinning disc hit you.

After that, there are some stairs, and another Roto-Disc. If you're not Raccoon Mario, or you don't want a Warp Whistle, skip to the next paragraph. If you're Raccoon Mario and you want a Warp Whistle, stand at the top of those stairs, then run to the right, then start flying as soon as your P-meter fills up, and keep flying up and to the right. When you can't go any farther, press Up on the directional pad to go through a hidden door. Go to the right to open a treasure chest that contains a Warp Whistle. You'll automatically complete the Fortress.

If you didn't fly as described in the previous paragraph, then go past the Roto-Disc, jump over some lava pits with Podoboos, get past another Roto-Disc, jump over one more lava pit with Podoboos, and you reach a ? block. Hit it to get a Super Mushroom or Super Leaf. If you got a Super Leaf and you want to go back and get a Warp Whistle, go left and jump over the lava pits, then go past the Roto-Disc and stop at the top of the stairs and read the previous paragraph.

Otherwise, go to the right, stomp on the Dry Bones or ignore it, and go to the right and press Up at the door to go through.

Avoid the Spikes

In this area, a ceiling of spikes slowly moves downward toward you. Go to the right where the spikes are slightly higher. You'll be safe from the spikes there.

When the spikes start to go back up again, go to the right and quickly jump over the gaps when the spikes are far enough above you that you won't hit them. Keep going to the right, where the ceiling is higher again, and when the spikes go all the way up, you will see a door in this corner. Press Up on the directional pad to go to the next room.

Boom Boom

Go to the right and you find the fortress boss, Boom Boom. He 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. 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

Afterward, the fortress will be in ruins, and the locked door in the level will disappear. If you lose all of your lives and have to continue the game, the levels that you cleared will no longer be cleared, but the locked door will still be gone, so you can skip some of those levels.

If you haven't fought the Hammer Bro yet, he might be reachable now. If you defeat him, you get a Starman.

You can now move on to World 1-5.