Armos Knights: These things are bigger than they are bad. Just hit each one with an arrow three times. The last one will turn red and try to crush you, but a well aimed arrow will do him in.
Lanmolas: These worms have one weak spot: their head. The best thing to do is watch where they come up, then do the Whirling Blade attack.
Moldorm: This giant worm is easy to defeat if you stay away from the edge of the platform. He won't take damage unless you hit him in the tail. Get him 6 times, but watch out! He goes much faster after the 5th hit. If he knocks you off the edge, you will have to start over.
Agahnim: He's Ganon's main dude, and a good wizard. When he shoots fireballs at you, make sure you're facing him and use the Master Sword to reflect the spell back to him. You can also use the bug net. Just avoid the other spells. When he goes to the top-center of the room and doesn't face you, go up and stand right next to him. He will then perform his Lightning Attack. Once you hit Agahnim 6 times, he will take you to the Dark World.
Helmasaur King: First you have to get rid of his mask with the hammer. When the mask breaks off, shoot arrows at the green thing on his back. Watch out for the fireballs and his tail.
Arrghus: As you can see, he's got friends! You must get rid of them first. Go across the room from him, and use the Hookshot to grab them, then go crazy with the sword. Watch out for the other ones too, because they will fly around the room. When you get rid of the little guys, Arrghus will jump up, try to crush you, then chase you around the room. Do the Whirling Blade attack a few times and he's gone!
Mothula: This huge moth is all show. All you really need to watch out for is the moving floor and the spikes. Use the fire rod as much as possible, then use the sword. Be careful because he will shoot stuff at you.
Blind The Thief: This guy's a pain in the butt. You first see him as a girl locked in a cell in Gargoyle's Domain. Now drag him to the empty boss's room. (Hopefully you have already bombed the floor above.) Take the girl into the light and watch out! To defeat him, you have to hit his head three times, but he has three heads, watch out for lazer beams and fireballs. If you successfully whack off all of them, you win.
Kholdstare: When you first get to his room, you will notice that he's trapped in a block of ice. Use the fire rod to melt it. Now use either the sword, or the fire rod to dispose of the three eyeballs. Watch out for the constant ice attacks.
Vitreous: He also has some friends. Stand in the left/right corner and kill the little eyeballs. Watch out for lightning attacks. Once the little eyes are defeated, Vitreous will chase you. Use the sword a few times to finish the job.
Trinexx: There are three steps to defeating this stone monster: First, Use the fire rod to stun the Ice Head, then finish him off with the sword. Then, use the ice rod to stun the Fire Head, then kill him with the sword. Watch out for Trinexx's head. It will shoot out at you and mess up your aim. Now Trinexx will turn into a snake like creature. Go for the clearly defined midsection. Hit him three times to finish the job.
Agahnim: It's just the same as the first one, only this time, there are two clones that will also shoot things at you. They can't be defeated.
Ganon: First, you have to use the sword and attack as much as possible. Watch out for his Trident and his Blazing Bats. Keep it up until he starts bragging about his secret. Then he will jump up and hit the floor really hard. All the outer tiles on one side of the room will collapse. The same thing will happen three more times. Then he will become invisible and put out the two torches on the bottom of the room. Go to the edge and light them with the fire rod, but watch out because a Fire snake will try to knock you off the edge so you'll have to start over. After you light them, ganon will appear. Hit him with the sword to stun him, the use the Silver arrows. Repeat the process three more times, and victory is yours!!