How to clear Vanilla Fortress in Super Mario World for the Super Nintendo Entertainment System and Game Boy Advance.

How to Clear Vanilla Fortress
Swim to the right. You can go through the chain of the Ball 'N' Chain without getting hurt. To the right, there are two Fishbones, followed by another Ball 'N' Chain.
There is a path down below that you can go through if you're Small Mario, where there are low spikes, then a Fishbone, then a pipe that you can go through. If you go through it, skip ahead to First Pipe on this page.
Otherwise, use the upper path to go to the right. There is a Fishbone and a Ball 'N' Chain, then there are spikes in the floor, followed by another Fishbone.
After that, there is a Prize Block that contains a Cape Feather, followed by another Fishbone.
The next area has spikes in the ceiling, and there are some darker spikes that will fall when you get close. There are also Fishbones, Bony Beetles, and Dry Bones that throw bones at you.
After that, there is a pipe. skip ahead to After the Pipe on this page.
First Pipe
There are two Fishbones to the right, followed by a Thwomp. Then the path splits in two. There is a Prize Block on the right that contains a Cape Feather, with two Bony Beetles under it. You can then go up to an upper path where there are coins, or keep going right. If you keep going right, there is a Fishbone, a Thwomp, a Dry Bones, a Ball 'N' Chain, and another Thwomp, followed by a Fishbone. Then there is a pipe.
After the Pipe
The pipe is followed by a Dry Bones, two Fishbones, and a Thwomp. You can optionally go up from there and visit the upper path. Otherwise, skip ahead to Before the Boss on this page.
Upper Path
If you go through the upper path instead, you encounter some Fishbones and Ball 'N' Chains, and you can get 12 coins.
Before the Boss
There is a Fishbone before two Ball 'N' Chains. If you go counterclockwise around the Gray Block that the first Ball 'N' Chain is attached to, you get a 1-Up Mushroom. The second Ball 'N' Chain is near the floor, where there is also a Dry Bones.
To the right of that, there are Fishbones and Bony Beetles, and if you have been to the Yellow Switch Palace, there is a Yellow Block that contains a Super Mushroom.
Go through the door to face the fortress boss, Reznor.
Reznor
There are four Reznor triceratops on four spinning platforms. You have to hit a platforms from underneath to defeat the Reznor on top of it. After you defeat the first Reznor, the floor will start to disappear, so jump onto an empty Reznor platform to avoid falling into the lava.
After the Level
After you defeat all four Reznors, the path to the east will unlock, and you can go to Butter Bridge 1.